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  1. 1. ZJ FRONT SUSPENSION AND AXLE 2-1 FRONT SUSPENSION AND AXLE CONTENTS page pageAXLE NOISE/VIBRATION DIAGNOSIS . . . . . . . . 12 MODEL 30 AXLE AND TUBE AXLE (2WD) . . . . 16AXLE SPECIFICATIONS . . . . . . . . . . . . . . . . . . . 40 TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . 40FRONT SUSPENSION . . . . . . . . . . . . . . . . . . . . . 8 WHEEL ALIGNMENT . . . . . . . . . . . . . . . . . . . . . . 4GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1 GENERAL INFORMATIONFRONT SUSPENSION The link/coil suspension allows each wheel to adapt The Grand Cherokee front suspension is a link/coil to different road surfaces without greatly affectingdesign comprised of (Fig. 1); the opposite wheel. Wheels are attached to a hub/• Drive axle (4WD), tube axle (2WD) bearings which bolts to the knuckles. The hub/bear-• Track bar ing is not serviceable and is replaced as a unit.• Stabilizer bar Steering knuckles pivot on replaceable ball studs at-• Upper and lower suspension arms tached to the axle tube yokes.• Coil springs The upper and lower suspension arms use bushings• Dual-action shock absorbers to isolate road noise. The suspension arms are bolted• Jounce bumpers to the frame and axle through the rubber bushings. Fig. 1 Front Suspension
  2. 2. 2-2 FRONT SUSPENSION AND AXLE ZJThe lower suspension arm uses cam bolts at the axleto allow for caster and pinion angle adjustment. Thesuspension arm travel is limited through the use ofjounce bumpers in compression and shocks absorbersin rebound. The coil springs control ride quality and maintainproper ride height. The coil springs mount up in thewheelhouse which is part of the unitized bodybracket. A rubber doughnut isolator is located be-tween the top of the spring and the body. The bottomof the spring seats on a axle pad and is retained witha clip. The shock absorbers dampen jounce and reboundmotion of the vehicle over various road conditions.The top of the shock absorbers are bolted to the body.The bottom of the shocks are bolted to the axlebrackets. The stabilizer bar is used to control vehicle bodyroll during turns. The spring steel bar helps to con-trol the vehicle body in relationship to the suspen-sion. The bar extends across the front underside ofthe chassis and connects to the frame rails. Links are Fig. 2 Model 30 Differential Coverconnected from the bar to the axle brackets. Stabi- • Ring gear (bolted to the differential case) rotateslizer bar mounts are isolated by rubber bushings. the case The track bar is used to control front axle lateral • Differential pinion gears (mounted on the pinionmovement. The bar is attached to a frame rail mate shaft in the case) rotate the side gearsbracket with a ball stud and isolated with a bushing • Side gears (splined to the axle shafts) rotate theat the axle bracket. shafts Suspension components which use rubber bushings During straight-ahead driving, the differential pin-should be tightened at vehicle ride height. This will ion gears do not rotate on the pinion mate shaft. Thisprevent premature failure of the bushing and main- occurs because input torque applied to the gears istain ride comfort. Bushings must never be lubricated. divided and distributed equally between the two side gears. As a result, the pinion gears revolve with theFRONT DRIVE AXLE pinion mate shaft but do not rotate around it (Fig. 3). The integral type housing, has the centerline of the When turning corners, the outside wheel mustpinion set below the centerline of the ring gear. The axles are equipped with A.B.S. brake systems.The A.B.S. tone rings are pressed onto the axle shaftnear the hub and knuckle. For additional informationon the A.B.S. system refer to Group 5, Brakes. The Model 30 axle has the assembly part numberand gear ratio listed on a tag. The tag is attached tothe housing cover (Fig. 2). Build date identificationcodes are stamped on the axle shaft tube cover side.STANDARD DIFFERENTIAL OPERATION The differential gear system divides the torque be-tween the axle shafts. It allows the axle shafts to ro-tate at different speeds when turning corners. Each differential side gear is splined to an axleshaft. The pinion gears are mounted on a pinionmate shaft and are free to rotate on the shaft. The Fig. 3 Differential Operation—Straight-Ahead Drivingpinion gear is fitted in a bore in the differential case travel a greater distance than the inside wheel in or-and is positioned at a right angle to the axle shafts. der to complete a turn. This difference must be com- In operation, power flow occurs as follows: pensated for in order to prevent the wheels from• Pinion gear rotates the ring gear scuffing and skidding through the turn. To accom-
  3. 3. ZJ FRONT SUSPENSION AND AXLE 2-3plish this the differential allows the axle shafts to mounts in the same bracketry as does the four wheelturn at unequal speeds (Fig. 4). In this instance, the drive front axle. The steering knuckles and hub bear-input torque applied to the pinion gears is not di- ing assemblies are the same as used on the Model 30vided equally. The pinion gears now rotate around drive axle.the pinion mate shaft in opposite directions. This al-lows the side gear and axle shaft attached to the out-side wheel to rotate at a faster speed. Fig. 4 Differential Operation—On TurnsTUBE AXLE (2WD VEHICLES) The front axle used on two wheel drive vehicles is Fig. 5 Front Axle—2WD Vehiclesa one-piece, tubular axle (Fig. 5). The tubular axle
  4. 4. 2-4 FRONT SUSPENSION AND AXLE ZJ WHEEL ALIGNMENTGENERAL INFORMATION camber. Incorrect camber will cause wear on the in- Four wheel alignment involves the correct position- side or outside edge of the tire (Fig. 1).ing of the wheels in relation to the vehicle. The posi- • TOE is the difference between the leading insidetioning is accomplished through suspension and edges and trailing inside edges of the front tires (Fig.steering linkage adjustments. An alignment is con- 1). Uneven wheel toe position cause’s unstable steer-sidered essential for efficient steering, good direc- ing, uneven tire wear and steering wheel off-center.tional stability and to minimize tire wear. The most The wheel toe position is the final front wheel align-important measurements of an alignment are caster, ment adjustment.camber toe and thrust angle. • THRUST ANGLE is the angle of the rear axle rel- Routine inspection of the front suspension ative to the vehicle center line. If this angle is off theand steering components is a good preventative vehicle may drift or wander.maintenance practice. Inspection also helps to • STEERING AXIS INCLINATION ANGLE is mea-ensure safe operation of the vehicle. sured in degrees. It is the angle that the steering• CASTER is the forward or rearward tilt of the knuckles are tilted (Fig. 1). The inclination angle hassteering knuckle from vertical. Tilting the top of the a fixed relationship with the camber angle. It will notknuckle forward provides negative caster. Tilting the change except when a spindle or ball stud is dam-top of the knuckle rearward provides positive caster. aged or bent. The angle is not adjustable and thePositive caster promotes directional stability. This damaged component(s) must be replaced to correctangle enables the front wheels to return to a straight mis-alignment.ahead position after turns (Fig. 1).• CAMBER is the inward or outward tilt of the CAUTION: Do not attempt to modify any suspen-wheel relative to the center of the vehicle. Tilting the sion or steering component by heating and bend-top of the wheel inward provides negative camber. ing.Tilting the top of the wheel outward provides positive Fig. 1 Wheel Alignment Angles
  5. 5. ZJ FRONT SUSPENSION AND AXLE 2-5 ALIGNMENT MEASUREMENTS AND ADJUSTMENTS Before each alignment reading the vehicle should be jounced (rear first, then front). Grasp each bumper at the center and jounce the vehicle up and down three times. Always release the bumper in the down position. CAMBER The wheel camber angle (Fig. 1) is preset. This an- gle is not adjustable and cannot be altered. CASTER Check the caster of the front axle for correct angle (fig. 1). Be sure the axle is not bent or twisted. Road test the vehicle and observe the steering wheel re- turn-to-center position. Low caster will cause poor steering wheel returnability. During the road test, turn the vehicle to both the left and right. If the steering wheel returns to the center position unassisted, the caster angle is correct. Fig. 2 Cam Adjuster However, if steering wheel does not return toward the center position unassisted, a low caster angle isPRE-ALIGNMENT INSPECTION probable. Before starting a front wheel alignment, the follow- Front aster can be adjusted by loosening and rotat-ing inspection and necessary corrections must be ing the cams on the lower suspension arm (Fig. 2).completed. Changing caster angle will also change the (1) Tires with the same recommended air pressure, front propeller shaft angle. The propeller shaftsize, and tread wear. Refer to Group 22, Wheels and angle has priority over caster. Refer to GroupTires for diagnosis information. (2) Front wheel bearings for wear. 16, Propeller Shafts for additional information. (3) Ball studs, steering linkage pivot points and TOE POSITIONsteering gear for looseness, roughness, binding or The wheel toe position adjustment should be the fi-wear. Refer to Group 19, Steering for additional in- nal adjustment.formation. (4) Wheels for excessive radial, lateral runout and (1) Start the engine and turn wheels both ways be-unbalance. Refer to Group 22, Wheels and Tires for fore straightening the steering wheel. Center and se-diagnosis information. cure the steering wheel. (5) Suspension components for wear and noise. (2) Loosen the adjustment sleeve clamp bolts (Fig.Check components for correct torque. Refer to Groups 3).2 and 3, Suspension and Axle for additional informa-tion. Fig. 3 Steering Linkage
  7. 7. ZJ FRONT SUSPENSION AND AXLE 2-7 ALIGNMENT SPECIFICATIONS Fig. 4 Drag Link and Tie Rod Clamp Location (3) Adjust the right wheel toe position with the same TOE-IN position as the right wheel. Positiondrag link. Turn the sleeve until the right wheel is at the clamp bolts as shown (Fig. 4) and tighten to 27the correct positive TOE-IN position. Position the N⅐m (20 ft. lbs.) torque. Make sure the toe settingclamp bolts as shown (Fig. 4) and tighten to 49 N⅐m does not change during clamp tightening.(36 ft. lbs.) torque. Make sure the toe setting does (5) Verify the right toe setting.not change during clamp tightening. (4) Adjust the left wheel toe position with the tierod. Turn the sleeve until the left wheel is at the
  8. 8. 2-8 FRONT SUSPENSION AND AXLE ZJ FRONT SUSPENSION INDEX page pageAxle Bushing Replacement . . . . . . . . . . . . . . . . . . . 9 Spring and Shock Diagnosis . . . . . . . . . . . . . . . . . 10Coil Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Stabilizer Bar . . . . . . . . . . . .................. 8Lower Suspension Arm . . . . . . . . . . . . . . . . . . . . . . 9 Track Bar . . . . . . . . . . . . . . .................. 8Service Information . . . . . . . . . . . . . . . . . . . . . . . . . 8 Upper Suspension Arm . . . . .................. 9Shock Absorber . . . . . . . . . . . . . . . . . . . . . . . . . . 10SERVICE INFORMATION Periodic lubrication of the front suspension (steer-ing) system components is required. Refer to Group0, Lubrication And Maintenance for the recom-mended maintenance schedule.CAUTION: Suspension components with rubberbushings should be tightened with the vehicle atnormal height. It is important to have the springssupporting the weight of the vehicle when the fas-teners are torqued. If springs are not at their normalride position, vehicle ride comfort could be affectedand premature bushing wear may occur. Rubberbushings must never be lubricated.TRACK BARREMOVAL (1) Raise and support the vehicle. (2) Remove the cotter pin and nut from the ballstud end at the frame rail bracket (Fig. 1). A puller tool may be necessary to separate theball stud from the frame rail bracket. (3) Remove the bolt and flag nut from the axleshaft tube bracket (Fig. 1). Remove the track bar.INSTALLATION Fig. 1 Track Bar (1) Install the track bar at axle tube bracket. STABILIZER BARLoosely install the retaining bolt and flag nut (Fig.1). REMOVAL (2) It may be necessary to pry the axle assembly (1) Raise and support the vehicle.over to install the track bar at the frame rail. Install (2) Disconnect the stabilizer bar links from thetrack bar at the frame rail bracket (Fig. 1). Install axle brackets (Fig. 2).the retaining nut on the stud. (3) Disconnect the stabilizer bar from the links. (3) Remove the supports and lower the vehicle. (4) Disconnect the stabilizer bar clamps from the (4) Tighten the bolt at the axle shaft tube bracket frame rails. Remove the stabilizer bar.to 75 N⅐m (55 ft. lbs.) torque. (5) Tighten the ball stud nut to 81 N⅐m (60 ft. lbs.) INSTALLATIONtorque. Install a new cotter pin. (1) Position the stabilizer bar on the frame rail and (6) Check alignment if a new track bar was in- install the clamps and bolts. Ensure the bar is cen-stalled. tered with equal spacing on both sides. Tighten the bolts to 54 N⅐m (40 ft. lbs.).
  9. 9. ZJ FRONT SUSPENSION AND AXLE 2-9 INSTALLATION (1) Position the upper suspension arm at the axle and frame rail (Fig. 3). (2) Install the bolts and finger tighten the nuts (Fig. 3). (3) Remove the supports and lower the vehicle. (4) Tighten the nut at the axle and frame bracket to 75 N⅐m (55 ft. lbs.) torque. AXLE BUSHING REPLACEMENT (1) Remove the upper suspension arm from axle. Refer to Upper Suspension Arm Removal in this Group. (2) Insert Spacer 7932-3 (J-35581-3) around the bushing in the axle bracket ears (Fig. 4). (3) Assemble and install Bushing Removal/In- staller (Fig. 4). (4) Remove the bushing by tightening the hex-head on Long Nut. Fig. 2 Stabilizer Bar (2) Install the links and grommets onto the stabi-lizer bar and axle brackets (Fig. 2). Tighten the nutat the connecting links at the axle bracket to 95 N⅐m(70 ft. lbs.) torque. (3) Tighten the stabilizer bar to connecting linknut to 36 N⅐m (27 ft. lbs.) torque. (4) Remove the supports and lower the vehicle.UPPER SUSPENSION ARMREMOVAL (1) Raise and support the vehicle. (2) Remove the upper suspension arm nut and boltat the axle bracket (Fig. 3). (3) Remove the nut and bolt (Fig. 3) at the framerail and remove the upper suspension arm. Fig. 4 Axle Bracket Bushing Removal For two-wheel drive axles and right side on Model 30 axle, do not remove Spacer 7932-3 (J- 35581-3) at this time. (5) Position the new bushing on Installer. (6) Install the bushing by tightening the hex-head on Long Nut (Fig. 5). Remove Spacer 7932-3 (J- 35581-3). (7) Install the upper suspension arm to axle. Refer to Upper Suspension Arm Installation in this Group. LOWER SUSPENSION ARM REMOVAL Fig. 3 Upper and Lower Suspension Arms (1) Raise and support the vehicle.
  10. 10. 2 - 10 FRONT SUSPENSION AND AXLE ZJ INSTALLATION (1) Position the lower suspension arm at the axle bracket and frame rail bracket. (2) Install the rear bolts and finger tighten the new nuts (Fig. 6). (3) Install a new cam bolt, cam and new nut in the axle. Re-align the reference marks. (4) Install the bolts and finger tighten the new nuts (Fig. 6). (5) Lower the vehicle. (6) Tighten the front and rear nuts to 115 N⅐m (85 ft. lbs.) torque. (7) Check the alignment if new parts were in- stalled. SPRING AND SHOCK DIAGNOSIS A squeak noise from the shock absorber can be pro- duced if movement between the rubber bushings and the metal occurs. This noise can usually be stopped by tightening the attaching nuts. If the squeak noise persists, inspect for damaged and worn bushings, Fig. 5 Axle Bracket Bushing Installation and attaching components. Repair as necessary. (2) Paint or scribe alignment marks on the cam ad- The shock absorbers are not refillable or adjust-justers and suspension arm for installation reference able. If a malfunction occurs, the shock absorber(Fig. 6). must be replaced. To test a shock absorber, hold it in an upright position and force the piston into and out of the cylinder four or five times. The action through- out each stroke should be smooth and even. SHOCK ABSORBER REMOVAL (1) Remove the nut, retainer and grommet from the upper stud in the engine compartment (Fig. 7). (2) Remove the lower nuts and bolts from the axle bracket (Fig. 7). Remove the shock absorber. INSTALLATION (1) Position the lower retainer and grommet on the upper stud. Insert the shock absorber through the shock tower hole. (2) Install the lower bolts and nuts. Tighten nuts to 28 N⅐m (250 in. lbs.) torque. (3) Install the upper grommet and retainer on the stud in the engine compartment. Install the nut and tighten to 23 N⅐m (17 ft. lbs.) torque. Fig. 6 Cam Adjuster COIL SPRING (3) Remove the lower suspension arm nut, cam REMOVALand cam bolt from the axle (Fig. 3). (1) Raise and support the vehicle. Position a hy- (4) Remove the nut and bolt from the frame rail draulic jack under the axle to support it.bracket and remove the lower suspension arm (Fig. (2) Paint or scribe alignment marks on the cam ad-6). justers and axle bracket for installation reference (Fig. 6). (3) Mark and disconnect the front propeller shaft from the axle.
  11. 11. ZJ FRONT SUSPENSION AND AXLE 2 - 11 (5) Disconnect the stabilizer bar link and shock ab- sorber from the axle. (6) Disconnect the track bar from the frame rail bracket. (7) Disconnect the drag link from the pitman arm. (8) Lower the axle until the spring is free from the upper mount. Remove the coil spring retainer bolt and remove the spring. (9) Remove the jounce bumper if necessary from the upper spring mount (Fig. 7). INSTALLATION (1) Install the jounce bumper on the upper spring mount. Tighten the bolts to 42 N⅐m (31 ft. lbs.) torque (Fig. 7). (2) Position the coil spring on the axle pad. Install the spring retainer and bolt. (3) Raise the axle into position until the spring seats in the upper mount. (4) Connect the stabilizer bar links and shock ab- sorbers to the axle bracket. Connect the track bar to the frame rail bracket. (5) Install the lower suspension arm to the axle. (6) Install the front propeller shaft to the axle. (7) Install drag link to pit man arm. (8) Remove the supports and lower the vehicle. (9) Tighten all suspension components to proper Fig. 7 Coil Spring & Shock Absorber torque. (4) Remove the lower suspension arm nut, camand cam bolt from the axle (Fig. 3).
  12. 12. 2 - 12 FRONT SUSPENSION AND AXLE ZJ AXLE NOISE/VIBRATION DIAGNOSIS INDEX page pageDriveline Snap . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Low Speed Knock . . . . . . . . . . . . . . . . . . . . . . . . . 13Gear and Bearing Noise . . . . . . . . . . . . . . . . . . . . 12 Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13General Information . . . . . . . . . . . . . . . . . . . . . . . 12GENERAL INFORMATION Excessive bearing preload may not be noisy. This Axle bearing problem conditions are usually caused condition will cause high temperature which can re-by: sult in bearing failure.• Insufficient or incorrect lubricant• Foreign matter/water contamination GEAR AND BEARING NOISE• Incorrect bearing preload torque adjustment• Incorrect backlash ( to tight) GEAR NOISE Axle gear noise can be caused by insufficient lubri- When serviced, the bearings must be cleaned thor- cant. Incorrect backlash, tooth contact, or worn/dam-oughly. They should be dried with lint free shop tow- aged gears can cause noise.els. Never dry bearings with compressed air. Gear noise usually happens at a specific speedThis will overheat them and brinell the bearing range. The range is 30 to 40 mph, or above 50 mph.surfaces. This will result in noisy operation af- The noise can also occur during a specific type ofter repair. driving condition. These conditions are acceleration, Axle gear problem conditions are usually the result deceleration, coast, or constant load.of: When road testing, accelerate the vehicle to the• Insufficient lubrication• Incorrect or contaminated lubricant speed range where the noise is the greatest. Shift out• Overloading (excessive engine torque) of gear and coast through the peak noise range. If• Exceeding vehicle weight capacity the noise stops or changes greatly, check for insuffi-• Incorrect clearance or backlash adjustment cient lubricant. Incorrect ring gear backlash, or gear Insufficient lubrication is usually the result of a damage can cause noise changes.housing cover leak. It can also be from worn axle Differential side and pinion gears can be checkedshaft or pinion gear seals. Check for cracks or porous by turning the vehicle. They usually do not causeareas in the housing or tubes. noise in straight ahead driving. These gears are Using the wrong lubricant will cause overheating loaded during vehicle turns. If noise does occur dur-and gear failure. Gear tooth cracking and bearing ing vehicle turns, the side or pinion gears could bespalling are indicators of this. worn or damaged. A worn pinion gear mate shaft can Axle component breakage is most often the result also cause a snapping or a knocking noise.of:• Severe overloading BEARING NOISE• Insufficient lubricant The axle shaft, differential and pinion gear bear-• Incorrect lubricant ings can all produce noise when worn or damaged.• Improperly tightened components Bearing noise can be either a whining, or a growling Common causes of overloading is from full throttle sound.acceleration. Overloading happens when towing Pinion gear bearings have a constant pitch noise.heavier than recommended loads. Component break- This noise changes only with vehicle speed. Pinionage can occur when the wheels are spun excessively. bearing noise will be higher because it rotates at aInsufficient or incorrect lubricants contribute to faster rate. Drive the vehicle and load the differen-breakage through overheating. Loose differential tial. If bearing noise occurs the pinion rear bearing iscomponents can also cause breakage. the source of the noise. If the bearing noise is heard Incorrect bearing preload or gear backlash will not during a coast, front bearing is the source.result in component breakage. This will cause accel- Worn, damaged differential bearings usually pro-erated wear and contribute to early failure. Mis-ad- duce a low pitch noise. Differential bearing noise isjustment will produce noise. If a mis-adjustment similar to pinion bearing. The pitch of differentialcondition is not corrected, component failure can re- bearing noise is also constant and varies only withsult. vehicle speed.
  13. 13. ZJ FRONT SUSPENSION AND AXLE 2 - 13 Axle shaft bearings produce noise and vibration • Bent axle shaftwhen worn or damaged. The noise generally changes Check for loose or damaged front end componentswhen the bearings are loaded. Road test the vehicle. or engine/transmission mounts. These componentsTurn the vehicle sharply to the left and to the right. can contribute to what appears to be a rear end vi-This will load the bearings and change the noise bration. Do not overlook engine accessories, bracketslevel. Where axle bearing damage is slight, the noise and drive belts.is usually not noticeable at speeds above 30 mph. All driveline components should be examined be- fore starting any repair.LOW SPEED KNOCK Refer to Group 22, Wheels And Tires for additional Low speed knock is generally caused by a worn U- information.joint or by worn side gear thrust washers. A wornpinion gear shaft bore will also cause low speed DRIVELINE SNAPknock. A snap or clunk noise when the vehicle is shifted into gear (or the clutch engaged), can be caused by:VIBRATION • High engine idle speed Vibration at the rear of the vehicle is usually • Loose engine/transmission/transfer case mountscaused by a: • Worn U-joints• Damaged drive shaft • Loose spring mounts• Missing drive shaft balance weight • Loose pinion gear nut and yoke• Worn, out-of-balance wheels • Excessive ring gear backlash• Loose wheel lug nuts • Excessive differential side gear-to-case clearance• Worn U-joint The source of a snap or a clunk noise can be deter-• Loose spring U-bolts mined with the assistance of a helper. Raise the ve-• Loose/broken springs hicle on a hoist with the wheels free to rotate.• Damaged axle shaft bearings Instruct the helper to shift the transmission into• Loose pinion gear nut gear. Listen for the noise, a mechanics stethoscope is• Excessive pinion yoke run out helpful in isolating the source of a noise.
  16. 16. 2 - 16 FRONT SUSPENSION AND AXLE ZJ MODEL 30 AXLE AND TUBE AXLE (2WD) INDEX page pageAxle Bushing Replacement . . . . . . . . . . . . . . . . . . 26 Drive Axle Assembly Replacement . . . . . . . . . . . . . 16Axle Shaft Oil Seals . . . . . . . . . . . . . . . . . . . . . . . 26 Final Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Axle Shaft— Cardan U-Joint . . . . . . . . . . . . . . . . . 20 General Information . . . . . . . . . . . . . . . . . . . . . . . 16Axle Shaft— CV-Joint . . . . . . . . . . . . . . . . . . . . . . 21 Hub Bearing and Axle Shaft . . . . . . . . . . . . . . . . . 19Backlash and Contact Pattern Analysis . . . . . . . . . 37 Lubricant Change . . . . . . . . . . . . . . . . . . . . . . . . . 17Cleaning/Inspection . . . . . . . . . . . . . . . . . . . . . . . . 29 Lubricant Specifications . . . . . . . . . . . . . . . . . . . . . 16Differential and Pinion Measurement . . . . . . . . . . . 32 Pinion Gear Assembly/Installation . . . . . . . . . . . . . 33Differential Assembly . . . . . . . . . . . . . . . . . . . . . . . 30 Pinion Gear Depth Information . . . . . . . . . . . . . . . 30Differential Disassembly . . . . . . . . . . . . . . . . . . . . 26 Pinion Removal/Disassembly . . . . . . . . . . . . . . . . . 28Differential Installation . . . . . . . . . . . . . . . . . . . . . . 36 Pinion Shaft Seal Replacement . . . . . . . . . . . . . . . 18Differential Removal . . . . . . . . . . . . . . . . . . . . . . . 26Differential Shim Pack Measurement and Steering Knuckle and Ball Studs . . . . . . . . . . . . . . 24 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35GENERAL INFORMATION LUBRICANT SPECIFICATIONS The housing for Model 30 front axles consists of an Multi-purpose, hypoid gear lubricant should beiron center casting with tubes on each side. The used for Model 30 axles. The lubricant should havetubes are pressed into and welded to the differential MIL-L-2105C and API GL 5 quality specifications.housing. MOPAR௡ Hypoid Gear Lubricant conforms to both of The integral type housing, hypoid gear design has these specifications.the centerline of the pinion set below the centerline • The factory fill for the Model 30 axle is SAE Ther-of the ring gear. mally Stable 80W-90 gear lubricant The axle has a vent used to relieve internal pres- • The factory installed lubricant quantity for thesure caused by lubricant vaporization and internal NON-DISCONNECT TYPE AXLE is 40Ϯ1 fluid oz.expansion. Refer to Group 0, Lubrication and Maintenance for The axles are equipped with semi-floating axle additional information.shafts, meaning that loads are supported by the hubbearings. The axle shafts are retained by nuts at the CAUTION: If axle is submerged in water, lubricanthub bearings. The hub bearings are bolted to the must be replaced immediately to avoid contamina-steering knuckle at the outboard end of the axle tube tion.yoke. The hub bearings are serviced as an assembly. The axles are equipped with ABS brake sensors. DRIVE AXLE ASSEMBLY REPLACEMENTThe sensors are attached to the knuckle assembliesand tone rings are pressed on the axle shaft. Use REMOVALcare when removing axle shafts as NOT to dam- (1) Raise vehicle and position support stands un-age the tone wheel or the sensor. der the frame rails behind the lower suspension arm The stamped steel cover provides a means for in- brackets.spection and servicing the differential. (2) Remove the front wheels. The Model 30 axle has the assembly part number (3) Remove the brake components and ABS brakeand gear ratio listed on a tag. The tag is attached to sensor (if equipped). Refer to Group 5—Brakes.the housing cover. Build date identification codes are (4) On 4WD vehicles, disconnect the axle ventstamped on the axle shaft tube cover side. hose. The differential case is a one piece design. The dif- (5) On 4WD vehicles, mark the drive shaft yokeferential pinion mate shaft is retained with a roll and axle pinion yoke for alignment reference. Discon-pin. Differential bearing preload and ring gear back- nect the drive shaft from the axle.lash is adjusted by the use of shims. The shims are (6) Disconnect the stabilizer bar link at the axlelocated between the differential bearing cones and bracket.case. Pinion bearing preload is set and maintained by (7) Disconnect the shock absorbers from axlethe use of a collapsible spacer. bracket. (8) Disconnect the track bar from the axle bracket.
  17. 17. ZJ FRONT SUSPENSION AND AXLE 2 - 17 (9) Disconnect the tie rod and drag link from the (15) Tighten the upper suspension arm nuts to 75steering knuckle. Disconnect the steering dampener N⅐m (55 ft. lbs.) torque. Tighten the lower suspensionfrom the axle bracket. arm nuts to 115 N⅐m (85 ft. lbs.) torque. (10) Support the axle with a hydraulic jack under (16) Tighten the track bar bolt at the axle bracketthe differential. to 75 N⅐m (55 ft. lbs.) torque. (11) Disconnect the upper and lower suspension (17) Check the front wheel alignment.arms from the axle bracket. (12) Lower the jack enough to remove the axle. LUBRICANT CHANGEThe coil springs will drop with the axle. The gear lubricant will drain quicker if the vehicle (13) Remove the coil springs from the axle bracket. has been recently driven. (1) Raise and support the vehicle.INSTALLATION (2) Remove the lubricant fill hole plug from the dif- ferential housing cover.CAUTION: Suspension components with rubber (3) Remove the differential housing cover andbushings should be tightened with the vehicle at drain the lubricant from the housing.normal height. It is important to have the springs (4) Clean the housing cavity and oil channels withsupporting the weight of the vehicle when the fas- a flushing oil, light engine oil or lint free cloth. Doteners are torqued. If springs are not at their normal not use water, steam, kerosene or gasoline forride position, vehicle ride comfort could be affected cleaning.and premature bushing wear may occur. Rubber (5) Remove the sealant from the housing and coverbushings must never be lubricated. surfaces. Use solvent to clean the mating surfaces. (6) Apply a bead of MOPAR௡ Silicone Rubber Seal- (1) Install the springs, retainer clip and bolts. ant to the housing cover (Fig. 1). Allow the sealant (2) Support the axle on a hydraulic jack under the to cure for a few minutes.differential. Position the axle under the vehicle. (3) Raise the axle with a floor jack and align itwith the spring pads. (4) Position the upper and lower suspension arm atthe axle bracket. Install bolts and nuts fingertighten. (5) Connect the track bar to the axle bracket andinstall the bolt. Do not tighten at this time. It is important that the springs support theweight of the vehicle when the track bar is con-nected. If the springs are not at their usual po-sition, the vehicle ride comfort could beaffected. (6) Install the shock absorber and tighten nuts to27 N⅐m (20 ft. lbs.) torque. (7) Install the stabilizer bar link to the axlebracket. Tighten the nut to 95 N⅐m (70 ft. lbs.)torque. (8) Install the drag link and tie rod to the steeringknuckles and tighten the nuts to 47 N⅐m (35 ft. lbs.)torque. Install the steering dampener to the axlebracket and tighten the nut to 75 N⅐m (55 ft. lbs.)torque. (9) Install the brake components and ABS brake Fig. 1 Typical Housing Cover With Sealantsensor (if equipped). Refer to Group 5—Brakes. Install the housing cover within 5 minutes af- (10) On 4WD vehicles, connect the vent hose to the ter applying the sealant. If not installed thetube fitting. sealant must be removed and another bead ap- (11) On 4WD vehicles, align the reference marks plied.and connect the drive shaft to the axle yoke. Tighten (7) Install the cover and any identification tag.the U-joint clamp bolts to 19 N⅐m (14 ft. lbs.) torque. Tighten the cover bolts in a criss-cross pattern to 41 (12) Check differential lubricant and add if neces- N⅐m (30 ft. lbs.) torque.sary. (8) Refill the differential with MOPAR௡ Hypoid (13) Install the wheel and tire. Gear Lubricant to the bottom of fill plug hole. (14) Remove the supports and lower the vehicle. (9) Install the fill hole plug and lower the vehicle.
  18. 18. 2 - 18 FRONT SUSPENSION AND AXLE ZJPINION SHAFT SEAL REPLACEMENTREMOVAL (1) Raise and support the vehicle. (2) Remove wheel and tire assemblies (3) Mark the propeller shaft yoke and pinion yokefor installation alignment reference. (4) Remove the propeller shaft from the yoke. (5) Rotate the pinion gear three or four times.Make sure brakes are not dragging during thisprocedure. (6) Measure the amount of torque (in Newton-meters or inch-pounds) necessary to rotate the piniongear with a torque wrench. Note the torque for in-stallation reference. It must be known to properlyadjust the pinion gear bearing preload torque Fig. 3 Seal Removalafter seal installation. (7) Remove the pinion yoke nut and washer. UseRemover C-452 and Wrench C-3281 to remove thepinion yoke (Fig. 2). (8) Mark the positions of the yoke and pinion gearfor installation alignment reference. Fig. 2 Pinion Yoke Removal Fig. 4 Pinion Seal Installation (9) Use Remover 7794A and slide hammer to re- on the pinion shaft will have to be replaced. Themove the pinion gear seal (Fig. 3). bearing preload torque will be re-adjusted after- ward.INSTALLATION (1) Apply a light coating of gear lubricant on the (4) Install a socket and inch-pound torque wrenchlip of pinion seal. Install seal with Installer D-163 on the pinion nut.and Handle C-4171 (Fig. 4). (5) Rotate the shaft with the torque wrench and (2) Align the installation reference marks and in- note the torque.stall yoke on the pinion gear with Installer W-162D. The required preload is equal to amount re- (3) Install a new nut on the pinion gear. Tighten corded during removal plus 0.56 N⅐m (5 in. lbs.).the nut only enough to remove the shaft end The used bearing preload torque must neverplay. exceed 2.25 N⅐m (20 in. lbs.) (6) Use Flange Wrench C-3281 to retain the yokeCAUTION: Exercise care during the bearing preload and shaft (Fig. 5). Tighten the shaft nut in verytorque adjustment. Do not over-tighten, or loosen small increments. Vehicles with Type 3 propellerand then re-tighten the nut. Do not exceed the bear- shaft use Flange Wrench C-3281 with 2 bolts in-ing preload torque. The collapsible preload spacer stalled into the flange (Fig. 6).
  19. 19. ZJ FRONT SUSPENSION AND AXLE 2 - 19 Fig. 6 Tightening Pinion Nut with Type 3 Shaft HUB BEARING AND AXLE SHAFT REMOVAL (1) Raise and support the vehicle. Fig. 5 Tightening Pinion Nut (2) Remove the wheel and tire assembly. (3) Remove the brake components from the axle, (7) Continue tightening the shaft nut in small in- refer to Group 5, Brakes.crements until the correct bearing preload torque is (4) Remove the cotter pin, nut retainer and axleattained. Tighten the pinion shaft nut: hub nut (Fig. 7).• No less than 217 N⅐m (160 ft. lbs.) torque (5) Remove the hub to knuckle bolts (Fig. 7). Re-• No greater than 352 N⅐m (260 ft. lbs.) torque move the hub from the steering knuckle and axle (8) Align the installation reference marks and at- shaft.tach the propeller shaft to the yoke. (6) Remove the disc brake rotor shield from the (9) Add API grade GL 5 hypoid gear lubricant to bearing carrier (Fig. 7).the differential housing, if necessary. (7) On 4WD vehicles, remove the axle shaft (10) Install wheel and tire assemblies from the housing. Avoid damaging the axle (11) Lower the vehicle. shaft oil seals in the differential. Fig. 7 Hub, Knuckle and Axle Shaft
  20. 20. 2 - 20 FRONT SUSPENSION AND AXLE ZJINSTALLATION (2) Locate a socket that is larger in diameter than (1) Thoroughly clean the axle shaft and apply a the bearing cap. Place the socket (receiver) againstthin film of Mopar Wheel Bearing Grease to the shaft the yoke and around the perimeter of the bearing capsplines, seal contact surface, hub bore. to be removed. Locate a socket that is smaller in di- (2) On 4WD vehicles, install the axle shaft into the ameter than the bearing cap. Place the socket (driv-housing and differential side gears. Avoid damaging er) against the opposite bearing cap. Position thethe axle shaft oil seals in the differential. yoke with the sockets in a vise (Fig. 9). (3) Install the hub bearing and brake dust shieldto the knuckle. (4) Install the hub to knuckle bolts and tighten to102 N⅐m (75 ft. lbs.) torque. (5) Install the hub washer and nut. Tighten thehub nut to 237 N⅐m (175 ft. lbs.) torque. Install thenut retainer and a new cotter pin (Fig. 7). (6) Install the brake components, refer to Group 5,Brakes. (7) Install the wheel and tire assembly. (8) Lower the vehicle.AXLE SHAFT— CARDAN U-JOINTDISASSEMBLY Single cardan U-joints are not serviceable. If defec-tive, they must be replaced as a unit. If the bearings,seals, spider or bearing caps are damaged or worn,replace the complete U-joint.CAUTION: Clamp only the forged portion of theyoke in the vise. Also, to avoid distorting the yoke, Fig. 9 Yoke Bearing Cap Removaldo not over tighten the vise jaws. (3) Compress the vise jaws to force the bearing cap into the larger socket (receiver). (1) Remove the bearing cap retaining snap rings (4) Release the vise jaws. Remove the sockets and(Fig. 8). bearing cap that was partially forced out of the yoke. (5) Repeat the above procedure for the remaining bearing cap. (6) Remove the remaining bearing cap, bearings, seals and spider from the propeller shaft yoke. CLEANING AND INSPECTION (1) Clean all the U-joint yoke bores with cleaning solvent and a wire brush. Ensure that all the rust and foreign matter are removed from the bores. (2) Inspect the yokes for distortion, cracks and worn bearing cap bores. (3) Replace the complete U-joint if any of the com- ponents are defective. ASSEMBLY (1) Pack the bearing caps 1/3 full of wheel bearing lubricant. Apply extreme pressure (EP), lithium-base lubricant to aid in installation. (2) Position the spider in the yoke. Insert the seals and bearings. Tap the bearing caps into the yoke Fig. 8 Axle Shaft Outer U-Joint bores far enough to hold the spider in position. (3) Place the socket (driver) against one bearing It can be helpful to saturate the bearing caps cap. Position the yoke with the socket wrench in awith penetrating oil prior to removal. vise.
  21. 21. ZJ FRONT SUSPENSION AND AXLE 2 - 21 (4) Compress the vise to force the bearing caps into If joint is noisy or worn, bypass following dis-the yoke. Force the caps enough to install the retain- assembly and replace entire unit and boot.ing clips. (5) Install the bearing cap retaining clips. DISASSEMBLY (6) Install the axle shaft, refer to Hub Bearing and (1) Remove retaining clamps from the outer CVAxle Shaft installation. joint and discard. Slide the boot off the outer joint and down the shaft.AXLE SHAFT— CV-JOINT (2) Remove the lubricant to expose the joint com- ponents (Fig. 10).HANDLING AND CLEANING PRECAUTIONS (3) Clamp the shaft in a vise (with soft jaws). Give Extreme care must be exercised to avoid punctur- a sharp tap to the top of the housing to dislodge jointing or tearing the boots. Also avoid damage to the from internal circlip. Slide the joint from the shaft.ABS tone ring pressed onto the CV-joint. (Fig. 11). The rubber material in shaft boots is not com-patible with oil, gasoline, or petroleum basedcleaning solvents. Do not expose the rubberboots to any of these fluids. Use only soap andwater to clean the rubber boots. After cleaning,the rubber boot must be thoroughly rinsed anddried.INSPECTION The most common failure of CV-joints is torn orripped boots and subsequent lubricant loss or con-tamination. Look for lubricant around the exterior ofboot. Check for a punctured or torn boot or retainingclamp loose. If joint was operating satisfactorily andgrease does not appear contaminated, replace boot.When a CV drive shaft is removed from the vehiclefor service, the boot should be properly cleaned. In- Fig. 11 Joint Removalspect the boot for cracks, tears and scuffed areas on (4) Remove the surplus lubricant. Apply installa-the surfaces. If any of these conditions exist boot re- tion alignment marks on the bearing hub, bearingplacement is recommended. cage and housing with dabs of paint (Fig. 12). Fig. 10 CV Joint Components
  22. 22. 2 - 22 FRONT SUSPENSION AND AXLE ZJ Fig. 12 Ball Access Fig. 14 Bearing Cage & Hub Removal (5) Place the stub shaft in a soft-jawed vise toavoid damage to the shaft splines. (6) Press down on one side of the bearing cage/hubto tilt the cage. This will provide access to a ball atthe opposite side of the cage. If the CV joint is tight,use a hammer and brass drift to loosen the bearinghub. Do not hit the bearing cage with the drift. (7) Remove the ball from the bearing cage (Fig.13). If necessary, a small pry bar can be used to prythe ball loose from the cage. Fig. 15 Bearing Hub Removal (1) Inspect the lubricant for grit, dirt, water dam- age and metallic particles. (2) Clean all the components with an appropriate solvent and dry them with compressed air. (3) Inspect the ball raceways in the housing for ex- cessive wear or scoring. (4) Examine the stub shaft splines and threads for damage. (5) Inspect the balls for pitting, cracks, scoring and Fig. 13 Ball Removal excessive wear. A dull exterior surface is normal. (6) Inspect the bearing cage for wear, grooves, rip- (8) Repeat the step above until all six balls are re- ples, cracks and chipping.moved from the bearing cage. (7) Inspect the bearing hub for excessive wear and (9) Tilt the bearing cage and hub to a vertical po- scoring on ball raceways.sition to remove (Fig. 14). (10) Insert one of the bearing hub lands into the ASSEMBLYadjacent cage window and roll it out of the cage (Fig. (1) Lightly apply lubricating oil to all joint compo-15). nents before assembling them. (2) Align the bearing hub, cage and housing ac-INSPECTION cording to the alignment reference marks. Polished contact surface areas on racewaysand bearing cage spheres are normal. If jointwas noisy or vibrated it should be replaced.
  23. 23. ZJ FRONT SUSPENSION AND AXLE 2 - 23 (3) Insert one of the bearing hub lands into a bear-ing cage window and roll it into the cage (Fig. 16).Rotate the bearing hub 90° to complete the installa-tion (Fig. 17). Fig. 18 Bearing Cage & Hub Installation Fig. 16 Bearing Hub Installation Fig. 19 Assembly Installed Fig. 17 Assembled Bearing Cage & Hub (4) Insert bearing cage/hub into the housing (Fig.18). Rotate the cage/hub 90° to complete the installa-tion. Ensure the tapered edge is facing outward(Fig. 19). (5) Apply the lubricant included with the replace-ment rubber boot to the ball raceways. Spread the lu-bricant equally between all the raceways. One packetof lubricant is sufficient to lubricate the joint. (6) Tilt the bearing hub and cage and install theballs in the raceways (Fig. 20). Fig. 20 Ball Installation In Raceway (7) Install the rubber boot on the axle shaft. En-sure the clamp sealing area is in the grooved sectionof the axle shaft. Install a new clamp.
  24. 24. 2 - 24 FRONT SUSPENSION AND AXLE ZJ (8) Engage the splines and install the joint ontothe shaft. Tap sharply with mallet until seated (Fig.21). Fig. 21 Joint Installation (9) Ensure that the snap ring is properly seated inthe housing. Pull the outer CV joint from the shaft to Fig. 22 Steering Knuckle Removal/Installationtest, it should not come off. LOWER BALL STUD REPLACEMENT (10) Install remaining amount of lubricant to cage (1) Position tools as shown to remove and installand balls. ball stud (Fig. 24). (11) Place the large diameter end of the rubberboot over the edge of the housing. Ensure that the KNUCKLE INSTALLATIONboot is not twisted. (1) Position the steering knuckle on the ball studs. (12) Ensure the clamp sealing area is in the (2) Install and tighten the bottom retaining nut togrooved section of the housing. Install a new clamp. 108 N⅐m (80 ft. lbs.) torque. Install new cotter pins. (13) Install the axle shaft, refer to Hub Bearing (3) Install and tighten the top retaining nut to 101and Axle Shaft installation. N⅐m (75 ft. lbs.) torque. Install new cotter pin. (4) Install the Hub Bearing and Axle Shaft. ReferSTEERING KNUCKLE AND BALL STUDS to the installation procedure. Ball Stud service procedures below require removal (5) Install tie-rod or drag link end onto the steer-of the hub bearing and axle shaft. Removal and in- ing knuckle arm. Install the ABS sensor wire andstallation of upper and lower ball stud requires use bracket to the knuckle, refer to Group 5, Brakes forof Tool Kit 6289 (J34503-A). proper set-up.KNUCKLE REMOVAL (1) Remove hub bearing and axle shaft. Refer tothe Removal procedures in this Group. (2) Remove tie-rod or drag link end from the steer-ing knuckle arm. Remove the ABS sensor wire andbracket from knuckle. (3) Remove the cotter pin from the upper ball studnut. Remove the upper and lower ball stud nuts. (4) Strike the steering knuckle with a brass ham-mer to loosen. Remove knuckle from axle tube yokes(Fig. 22).UPPER BALL STUD REPLACEMENT (1) Position tools as shown to remove and installball stud (Fig. 23).
  25. 25. ZJ FRONT SUSPENSION AND AXLE 2 - 25 Fig. 23 Upper Ball Stud Remove/Install Fig. 24 Lower Ball Stud Remove/Install
  26. 26. 2 - 26 FRONT SUSPENSION AND AXLE ZJAXLE BUSHING REPLACEMENT CAUTION: Do not spread over 0.38 mm (0.015 in.). If Refer to Axle Bushing Replacement in the Front the housing is spread too much, it could be dis-Suspension section. torted or damaged.DIFFERENTIAL REMOVAL (5) Separate the housing a maximum of 0.38 mm To service the differential the axle shafts must be (0.015 in.). Measure the distance with the dial indi-removed. Refer to the removal procedures in this cator (Fig. 26).Group. (6) Remove the dial indicator. (1) Note the installation reference letters (7) Pry the differential case loose from the housing.stamped on the bearing caps and housing ma- To prevent damage, pivot on housing with the end ofchined sealing surface (Fig. 25). the pry bar against spreader (Fig. 27). Fig. 25 Bearing Cap Identification (2) Remove the differential bearing caps. (3) Position Spreader W-129B with the tool dowelpins seated in the locating holes (Fig. 26). Install theholddown clamps and tighten the tool turnbuckle fin-ger-tight. Fig. 27 Differential Removal (8) Remove the case from housing. Mark or tag bearing cups indicating which side they were re- moved. Remove spreader from housing. AXLE SHAFT OIL SEALS (1) Remove the inner axle shaft seals with a pry bay. (2) Install oil seals with Discs 6798 and Turn- buckle 6797 (Fig. 28). Tighten tool until disc bottoms in housing. DIFFERENTIAL DISASSEMBLY (1) Remove the bearings from the differential case with Press C-293PA, Plug C-293-3, Adapter C-293-39 (Fig. 29). Fig. 26 Spread Differential Housing Place adapter rings so they do not damage the bearing cage. (4) Install a pilot stud at the left side of the differ- (2) Remove bearing shims from case hubs andential housing. Attach Dial Indicator to housing pilot mark them (with hub identity) for assembly refer-stud. Load the indicator plunger against the opposite ence. Record the thickness of the shims.side of the housing (Fig. 26) and zero the indicator. (3) Clamp the differential case in a vise equipped with soft jaws. Remove and discard the ring gear
  27. 27. ZJ FRONT SUSPENSION AND AXLE 2 - 27 Fig. 30 Ring Gear Removal Fig. 28 Axle Shaft Oil Seal Installation Fig. 31 Mate Shaft Lock Pin Removal Fig. 29 Differential Bearing Removalbolts. Tap the ring gear with a rawhide or plasticmallet and remove (Fig. 30). (4) Use a drift to remove the pinion gear mateshaft lock pin (Fig. 31).
  28. 28. 2 - 28 FRONT SUSPENSION AND AXLE ZJ (5) Remove the mate shaft with a drift and ham-mer (Fig. 32). Fig. 34 Pinion Yoke Removal damaged. This will damage the front bearing Fig. 32 Mate Shaft Removal rollers and bearing cup. The front bearing and (6) Rotate the differential side gears and remove cup must be replaced.the pinion mate gears and thrust washers (Fig. 33). (3) Remove the pinion gear seal with a slide ham- mer or pry out with bar. Fig. 33 Pinion Mate Gear Removal Fig. 35 Remove Pinion Gear (7) Remove the differential side gears and thrust (4) Remove oil slinger, front bearing.washers. (5) Remove the front pinion bearing cup and seal (8) Remove the case from the vise. with Remover D-147 and Handle C-4171 (Fig. 36). (6) Remove the rear bearing cup from housing withPINION REMOVAL/DISASSEMBLY Remover D-149 and Handle C-4171 (Fig. 37). (1) Remove the pinion yoke nut and washer. Use (7) Remove the collapsible preload spacer (Fig. 38).Remover C-452 and Wrench C-3281 to remove the (8) Remove the inner bearing from the pinion withpinion yoke (Fig. 34). Puller C-293PA and Adapter C-293-39 (Fig. 39). (2) Drive out pinion gear from housing with raw- Place adapter rings so they do not damagehide or plastic hammer (Fig. 35). Catch the pinion the bearing cage.with your hand to prevent it from falling and being
  29. 29. ZJ FRONT SUSPENSION AND AXLE 2 - 29 Fig. 36 Front Bearing Cup Removal Fig. 38 Collapsible Spacer Fig. 37 Rear Bearing Cup Removal (9) Remove the oil slinger (select thickness-produc- Fig. 39 Inner Bearing Removaltion) from the pinion gear shaft. Record the thick- Clean the axle shaft tubes with a stiff wire brushness of slinger. or clean cloth. Inspect the components for;CLEANING/INSPECTION • Smooth appearance with no broken/dented sur- Wash differential components with cleaning solvent faces on the bearing rollers or the roller contact sur-and dry with compressed air. Do not steam clean facesthe differential components. • Bearing cups must not be distorted or cracked Wash bearings with solvent and towel dry, do spin • Machined surfaces should be smooth and withoutdry bearings with compressed air. Cup and bearing any raised edgesmust be replaced as matched sets only.
  30. 30. 2 - 30 FRONT SUSPENSION AND AXLE ZJ• Raised metal on shoulders of cup bores should beremoved with a hand stone• Wear and damage to pinion gear mate shaft, pin-ion gears, side gears and thrust washers. Replace asa matched set only.• Ring and pinion gear for worn and chipped teeth• Ring gear for damaged bolt threads. Replaced as amatched set only.• Pinion yoke for cracks, worn splines, pitted areas,and a rough/corroded seal contact surface. Repair orreplace as necessary.• Preload shims for damage and distortion. Installnew shims if necessary.DIFFERENTIAL ASSEMBLY (1) Install the following components in the differ-ential case.• Differential side gears and thrust washers• Pinion gears and thrust washers• Pinion gear mate shaft (align holes in shaft andcase) (2) Install and seat the locking roll pin in the dif-ferential case and mate shaft with a punch and ham- Fig. 41 Ring Gear Bolt Installationmer (Fig. 40). Peen metal part of case over pin in two (5) Lubricate all differential components with aplaces a 180 degrees apart. light coat of grease or hypoid gear lubricant. If replacement gears and thrust washers wereinstalled, it is not necessary to measure the PINION GEAR DEPTH INFORMATIONgear backlash. Correct fit is due to close ma- Ring and pinion gears are supplied as matched setschining tolerances during manufacture. only. The identifying numbers for the ring and pinion gear are etched into the face of each gear (Fig. 42). A plus (+) number, minus (-) number or zero (0) is etched into the face of the pinion gear. This number is the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion etched with a (0). The standard setting from the cen- terline of the ring gear to the back face of the pinion is 92.1 mm (3.625 inches) for Model 30 axles (Fig. 43). The standard depth provides the best teeth con- tact pattern. Fig. 40 Mate Shaft Pin Installation (3) Invert the differential case and start two ringgear bolts. This will provide case-to-ring gear bolthole alignment. (4) Install new ring gear bolts and alternately Fig. 42 Pinion Gear ID Numberstighten to 95-122 N⅐m (70-90 ft. lbs.) torque (Fig. 41).
  31. 31. ZJ FRONT SUSPENSION AND AXLE 2 - 31 THE BUTTON END ON THE PINION GEAR HEADIS NO LONGER A MACHINED-TO-SPECIFICATIONSSURFACE. DO NOT USE THIS SURFACE FOR PIN-ION DEPTH SET-UP OR CHECKING (Fig. 43). Fig. 43 Pinion Gear Head Fig. 44 Shim and Slinger Location Compensation for depth variance is achieved by a se- to compensate for the difference in depth vari-lected thickness oil slinger (production) or shims (ser- ances. Refer to the Depth Variance charts.vice). The slinger is placed between the inner pinion Note where Old and New Pinion Marking columnsbearing cone and gear head (Fig. 44). The shim pack isplaced under the inner (rear) bearing cup. To change intersect. Intersecting figure represents plus or mi-the pinion adjustment, shims are available in thick- nus amount needed.nesses of 0.003, 0.005, and 0.010 inch. If equipped, the For example, if old pinion is plus (+) 1 and the newoil slinger or baffle must be measured and the pinion is minus (-) 3, intersecting figure is (+) 0.004thickness included with the total shim pack. inch (0.10 mm). Add this amount to the original If a new gear set is being installed, note the shim. Or if the old pinion is (-) 3 and the new pinionnumber etched into both pinion gears. Add or is (-) 2, intersecting figure is (-) 0.001 inch (0.025subtract the thickness of original depth shims PINION GEAR DEPTH VARIANCE
  32. 32. 2 - 32 FRONT SUSPENSION AND AXLE ZJmm). Subtract this amount from original shim. Referto the Pinion Gear Depth Variance Chart.DIFFERENTIAL AND PINION MEASUREMENTDIFFERENTIAL ZERO END PLAYMEASUREMENT (1) Place Master Differential Bearing D-134(D-348) on the case hubs (Fig. 45). Fig. 46 Differential Case End Play Measurement PINION GEAR DEPTH MEASUREMENT Pinion gear depth measurement is necessary when; • Axle housing or differential case is replaced • Pinion select shim pack is unknown • Ring and pinion gears are replaced Measurements are done with pinion cups and pin- ion bearings installed in housing. Take measure- Fig. 45 Master Bearing Tools On Hubs ments with Pinion Gauge Set 6774, Pinion Block 6733 and Dial Indicator C-3339 (Fig. 47). (2) Install a pilot stud at the right side of housing.Attach Dial Indicator to the pilot stud. Load indica-tor plunger against the back of the ring gear (Fig.46). (3) Insert a small pry bar between the bearing capand left side of differential case. Pry the case as faras possible to right side (Fig. 46). Zero the dial indi-cator pointer. (4) Pry the case to left side and record the traveldistance. The measurement above is the shim thicknessnecessary for case zero end-play. The totalthickness will be determined during the ringgear backlash adjustment. (5) Remove indicator and pilot stud. Fig. 47 Pinion Gear Depth Gauge Tools
  33. 33. ZJ FRONT SUSPENSION AND AXLE 2 - 33 (1) Assemble Pinion Gauge Set, Pinion Block andpinion bearings. Install assembly into differentialpinion gear bore and hand tighten cone (Fig. 48). Fig. 50 Pinion Gear Depth Measurement tal shim pack thickness. Include oil slinger or baf- fle thickness with the total shim pack Fig. 48 Pinion Height Block thickness. (6) Remove the measurement tools from the differ- (2) Place Arbor Disc 6732 on Arbor D-115-3 and po- ential housing.sition in the bearing cradles (Fig. 49). Install differ-ential bearing caps on Arbor Discs and tighten caps PINION GEAR ASSEMBLY/INSTALLATIONsnug only. (1) Place the needed shim pack thickness in the Arbor Discs have different steps to fit other pinion gear rear bearing bore (service only). Installaxle sizes. Pick correct size step for axle beingserviced. the bearing cup with Installer D-146 and Driver Handle C-4171 (Fig. 51). Ensure cup is correctly seated. Fig. 49 Gauge Tools In Housing (3) Firmly place Scooter Block and Dial Indicatoron pinion height block tool and zero the dial indicatorpointer. (4) Slide the Scooter Block across the arbor whileobserving indicator (Fig. 50). Record the longesttravel distance, whether inward (-) or outward (+),indicated by the pointer. Fig. 51 Pinion Rear Bearing Cup Installation The plunger travel indicated, plus or minusthe variance etched in the gear is the required (2) Install the pinion front bearing cup with In-thickness for the depth shims. staller D-144 and Handle C-4171 (Fig. 52). (5) Measure the thickness of each depth shim witha micrometer. Then combine the shims needed for to-
  34. 34. 2 - 34 FRONT SUSPENSION AND AXLE ZJ (4) Install a new collapsible preload spacer on pin- ion shaft. (Fig. 54). Fig. 52 Pinion Front Bearing Cup Installation (3) If used, place the oil slinger on the pinion gear.Install the rear (inner) bearing on the pinion gearwith Installer W-262 (Fig. 53). Fig. 54 Collapsible Preload Spacer (5) Install pinion front bearing and oil slinger. Ap- ply a light coating of gear lubricant on the lip of pin- ion seal. Install seal with Installer D-163 and Handle C-4171 (Fig. 55). Fig. 53 Rear Bearing Installation Fig. 55 Pinion Seal Installation
  35. 35. ZJ FRONT SUSPENSION AND AXLE 2 - 35 (6) Install pinion gear into differential housing. (7) Install yoke with Installer W-162D and WrenchC-3281 (Fig. 56). Fig. 57 Tightening Pinion Nut Fig. 56 Pinion Yoke Installation (8) Install the yoke washer AND A NEW NUT onthe pinion gear. Tighten the nut to 216 N⅐m (160ft. lbs.).CAUTION: Never loosen the pinion gear nut to de-crease the pinion gear bearing preload torque. If thespecified preload torque exceeds 352 N⅐m (260 ft.lbs.) a new collapsible spacer must be installed.The torque sequence will have to be repeated. (9) Use Flange Wrench C-3281 to retain the yoke(Fig. 57). Slowly tighten the nut in small incrementsuntil the rotating torque is achieved. Measure thepreload torque frequently to avoid over-tight-ening the nut. (10) Check bearing preload torque with an inchpound torque wrench (Fig. 58). The torque necessaryto rotate the pinion gear should be;• Original Bearings: 1 to 3 N⅐m (10 to 20 in. lbs.). Fig. 58 Check Pinion Gear Torque• New Bearings: 1.5 to 4 N⅐m (15 to 35 in. lbs.). Ensure ring and pinion gear teeth are tightly meshed. Zero the indicator.DIFFERENTIAL SHIM PACK MEASUREMENT AND (4) Insert a small pry bar between the bearing capADJUSTMENT and left side of differential case. Pry the case as far (1) Place Master Differential Bearing D-134 as possible to right side (Fig. 60). Zero the dial indi-(D-348) on the case hubs. cator pointer. (2) Place Differential assembly in the housing. As- (5) Repeat the measurement several times to checksemble Differential bearing caps. consistency. Record the travel distance. (3) Install a pilot stud at the left side of housing. The measurement above shows shim thick-Attach Dial Indicator to housing. Load the indicator ness necessary to eliminate ring gear backlash.plunger against the back of the ring gear (Fig. 59). Subtract this thickness from case zero end-play
  36. 36. 2 - 36 FRONT SUSPENSION AND AXLE ZJ ing on the hub with Bearing Installer C-3716A and Driver Handle C-4171 (Fig. 61). Fig. 59 Shim Pack Measurementshim thickness (Fig. 60). The shims must be Fig. 61 Differential Bearing Installationplaced at the ring gear side between the caseand bearing. (10) Position the remaining zero end-play shims on hub at opposite side of case. Include an additional 0.015 in. (0.38 mm) thick shim on this hub. This will provide the required differential bearing preload. (11) Install bearings on hubs with Installer C-3716A and Handle C-4171 (Fig. 61). (12) Match each bearing cup with bearing (origi- nal). Install the cups on the bearings. DIFFERENTIAL INSTALLATION (1) Position Spreader W-129B with the tool dowel pins seated in the locating holes (Fig. 62). Install the holddown clamps and tighten the tool turnbuckle fin- ger-tight. Fig. 60 Shim Pack Calculations (6) Remove indicator and pilot stud. (7) Remove the differential case from housing. (8) Remove the master bearing tools from the dif-ferential case hubs. (9) Position the backlash shims (with determinedthickness) on case hub (ring gear side). Install bear- Fig. 62 Spread Differential Housing
  37. 37. ZJ FRONT SUSPENSION AND AXLE 2 - 37 (2) Install a pilot stud at the left side of the differ- If backlash must be adjusted, transfer shims fromential housing. Attach Dial Indicator to housing pilot one side of carrier to the other side. Adjust the back-stud. Load the indicator plunger against the opposite lash accordingly (Fig. 64). DO NOT INCREASEside of the housing (Fig. 63) and zero the indicator. THE TOTAL SHIM PACK THICKNESS, EXCES- SIVE BEARING PRELOAD AND DAMAGE MAYCAUTION: Do not spread over 0.38 mm (0.015 in). If OCCUR.the housing is over-separated, it could be distortedor damaged. (3) Separate the housing enough to install the casein the housing. Measure the distance with the dialindicator (Fig. 62). (4) Remove the dial indicator. (5) Install case in the housing. Tap the differentialcase to ensure the bearings are fully seated. Removethe spreader. (6) Install the bearing caps at their original loca-tions. Tighten the bearing cap bolts to 61 N⅐m (45 ft.lbs.) torque.BACKLASH AND CONTACT PATTERN ANALYSIS (1) Rotate assembly several revolutions to seatbearings. Measure backlash at three equally spacedlocations around the perimeter of the ring gear witha dial indicator (Fig. 63). Fig. 64 Backlash Shim Adjustment If the mesh and backlash steps have been followed in the procedures above, good gear teeth contact pat- terns should exist. The ring gear teeth contact patterns will show if the pinion gear depth shim(s) have the correct thick- ness. It will also show if the ring gear backlash has been adjusted correctly. The backlash must be main- tained within the specified limits until the correct tooth contact patterns are obtained. (2) Apply a thin coat of hydrated ferric oxide to the drive and coast side of the ring gear. (3) Rotate the ring gear several revolutions in both directions while a load is being applied. Insert a pry bar between the differential housing and the case Fig. 63 Ring Gear Backlash Measurement flange. This action will produce distinct contact pat- The ring gear backlash must be within 0.005 - terns on both the drive side and coast side of the ring0.008 inch (0.12 - 0.20 mm). It cannot vary more gear teeth.than 0.002 inch (0.05 mm) between the points (4) Note patterns in compound. Refer to (Fig. 65)checked. for interpretation of contact patterns and adjust ac- cordingly.
  38. 38. 2 - 38 FRONT SUSPENSION AND AXLE ZJ Fig. 65 Gear Tooth Contact Patterns