The document discusses lubrication and gear types used in manual transmissions. It describes how counter shaft gears rotate in lubricant which is directed by troughs to shaft bearings and bushings. Transmissions can also have pumps to distribute lubricant through drilled oil passages to gear bearings. Vent plugs relieve internal pressure and leaks can occur if plugged. Common gear lubrication types for newer manual transmissions include 75W-90 GL4/GL5, 80W-90 GL4/GL5, and Dextron IV. Transmission cases use formed-in-place gaskets made of room temperature vulcanizing silicone or anaerobic sealants. The document also lists common transmission problems and testing procedures

24.  Counter shaft gears rotate in lubricant
• Carries lubricant to output shaft gears and troughs
 Troughs or oiling funnels direct oil to
shaft bearings and bushings
 Some transmissions have Pumps
which pump fluid down shafts
• Speed gears and shafts have drilled oil passages
• Distributes lubricant to gear bearings
 Transmission vent
• Relieve internal pressure (heat)
• If plugged, venting occurs past seal, resulting in leaks

25.  GL-1
• Straight mineral oil/ Use additives
• Used in non-synchromesh transmissions
• Not suitable for modern transmissions
 GL-2
• A designation for worm gear drives
• Used in mostly industrial applications
 GL-3
• Contains mild EP additives
• Used in MTs with spiral bevel final drives
 GL-4
• Used in MTs with hypoid final drives; contains half additives found in
GL-5
 GL-5
• Contains enough EP additive to lubricate hypoid gears in drive axles

26.  Newer Manual transmissions use
following gear lubrication types:
• 75W-90 GL4/GL5
• 80W-90 GL4/GL5
• Dextron IV
• Consult vehicle repair manual for
specific lubrication information or
shift quality will decrease!

27.  Transmission Cases Use Formed-In-Place
Gaskets (FIPG):
• Room Temperature Vulcanizing (RTV)
 Made from silicone
 Sets to rubber-like material fast when
exposed to air
• Anaerobic sealants
 Similar in function to RTV
 Used to seal gaskets or to form gaskets
 Cures in absence of air

47. TECHNICIAN HANDBOOK PAGE 4-25

48. TECHNICIAN HANDBOOK PAGE 4-26

49. TECHNICIAN HANDBOOK PAGE 4-30

50. TECHNICIAN HANDBOOK PAGE 4-31

51. TECHNICIAN HANDBOOK PAGE 4-33

56.  Oil leakage
 Hard to shift
 Will not shift
 Locked in gear
 Jumps out of gear
 Gear clash/grinding during shift
 Noisy in neutral
 Noisy in one gear
 Noisy in all gears
 Gear roll over noise

57. Disengage clutch by depressing clutch
pedal
Shift transmission/transaxle into gear &
shift to neutral
Shift back to originally selected gear
Note amount of effort required
Repeat check on all remaining gears
Note any shift requiring increased effort

58.  To perform:
• Set parking brake & start engine
• Idle engine in neutral
• Note unusual noises
 Disengage clutch & shift into first gear; note:
• Amount of effort required to complete shift & compare
to engine-off test
• Unusual noises
 Release parking brake
• Engage clutch to move vehicle slightly
• Check for unusual noises or movement
 Repeat process for each gear position

59.  Warm up transmission before road test
 Check transmission oil level
 With vehicle stationary in neutral, and engine
idling:
• Disengage clutch
• Engage clutch & listen for noise
 Repeat steps above & wait three seconds
• Shift into reverse, first gear, & back to reverse
• Wait twenty seconds & repeat
• Note differences in noise, shifting ability, pedal
movement, and position of clutch engagement

60.  Shift into reverse, release pedal, & back up,
increasing engine speed to 2,500 rpm
• Note any noises
 Drive vehicle on road:
• Start in first gear, accelerate, & upshift at
4,000 rpm through all gears – note shift
quality & noises (Observe speed limits & safety)
• Decelerate using engine braking – downshift
in each gear & note noises
• On highway, drive in fourth gear at 60 mph, accelerate
& shift into fifth gear – note any problems

67.  Always double check sleeve orientation on
assembly!
 Check for free rotation many times through build
and after pressing on gears/bearings!
 Snap rings and Snap ring grooves
• Check for wear
• Snap rings have a round and flat side
 Flat side goes with thrust
 Gear Teeth
• Check for chips and wear
• Chips in non contact area can be ground down
• Always replace gears in sets or noise will occur

68.  Synchronizer rings
• Replace all of them
• Check contact area and lap if
needed
 Check sleeves and speed
gears
• If dog teeth are worn replace
 Main and counter shaft
bearings
• Replace at time of overhaul
 0” axial play on roller ball
bearings
 Preload tapered roller bearings
 Check bearing retainers for wear

69. Final drive bearings
• Replace and set preload
 Usually done with shims
• Check spider and side gears for excess back-lash
• Check pinion pin for play
Check for free rotation
Bench shift several times