1. Trouble shooting in GearBox

2. Location of Gearbox
The manual transmission in front engine and
rear-wheel-drive vehicle is located between
the clutch and the driveshaft.
In a car with a front engine and front-wheel-
drive, the transmission is located between the
clutch and the differential in the transaxle.

3. Purpose of transmission
• Provides speed and torque conversion.
• Facilitates change of direction of output
shaft for reversing
• Gearbox are used to reduce load on the
engine by manipulating torque and speed.

4. Manual Transmission

5. Gear lubricants
Need:
–Lubricate, prevent wear
–Reduce friction
–Protect against rust and corrosion
–Clean & Cool.
Additive:
EP(Extreme-pressure), to increase the load-carrying
capacity.
Examples:
SAE 75W, 75W-80, 80W-90, 85W-95, 90 or 140.

6. Diagnosis
• Road Test:
– Noise.
– Improper operation.

7. Trouble-Diagnosis
• Hard shifting into gear
–Gearshift linkage out of adjustment.
–GSL need lubrication.
–Clutch not disengaging
–Excess clutch pedal free play
–Synchronizer tight on shaft splines
–Gear teeth battered

8. • Transmission sticks in gear:
–Gearshift linkage out of adjustment or disconnected.
–GSL need lubrication.
–Clutch not disengaged.
–Detent ball stuck.
–Synchronizing unit stuck

9. • Transmission slip out of gear
–Weak lockout spring.
–Bearing or gear worn.
–End play of shaft or gear excessive.
–Synchronizer defect.
–Clutch misalignment.
–Input shaft retainer loose.
–Broken engine mount.

10. • No power through transmission
–Clutch slipping
–Gear teeth stripped
–Shifting fork broken
–Gear or shaft broken
–Drive key or spline sheared off

11. • Transmission noisy in neutral
– Gear worn or teeth broken or chipped.
– Bearing worn or dry.
– Input-shaft bearing defect.
– Pilot bushing worn.
– Transmission misaligned with engine.
– Counter shaft worn or broken.

12. • Transmission noisy in gear:
–Clutch friction disk defective.
–Incorrect or insufficient lubricant.
–Main bearing worn or dry.
–Synchronizers worn or damaged.
–Speedometer gear worn.

13. • Gear clash during shift
– Synchronizer defective.
– Clutch does not disengaged, pedal free play(incorrect).
– Idle speed excess.
– Pilot bushing binding
– Incorrect lubricants
– GSL out of adjustment

14. • Transmission noisy in reverse
– Reverse idler gear or bushing worn or damaged.
– Reverse gear or shaft worn or damaged.
– Counter gear worn or damaged.
– Shift mechanism damaged.

15. • Oil leaks:
– Foaming die to incorrect lubricants
– Oil level too high
– Gasket broken or missing
– Drain plug loose
– Transmission retainer bolt loose
– Drive line yoke worn
– Extension case crake

16. Service
• Remove shift lever
• Rise the vehicle
• Mark(reinstallation) the rear axle flange and drive shaft.
Remove driveshaft.
• Drain the lubricants from the transmission.
• remove the sensor cable adopter.
• Disconnect the drive shaft.
• Support the engine with jack. Remove the transmission.

17. • Remove the upper bolt attached the transmission to
the clutch housing and install guide pin(to prevent
clutch damage) in the holes.
• Slide the transmission rearward until the clutch shaft
clears the clutch.