Trouble shooting in GearBox

Location of GearboxThe 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.

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.

Manual Transmission

Gear lubricantsNeed:

–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.

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

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

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

• 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.

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

• 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.

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

• 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

• 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.

• 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

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.

• 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.