Service Information

Spark

Transmission Noisy

Many noises that appear to come from the transmission may actually originate with other sources such as the tyres, road surfaces, wheel bearings, or the engine and exhaust system.

Identify the cause of any noise before attempting to repair the clutch, the transmission, or their related linkages.

To verify suspected transmission noises:

Select a smooth, level asphalt road to reduce tyre and resonant body noise.
Drive the vehicle far enough to warm up all the lubricants thoroughly.
Record the speed and the gear range of the transmission when the noise occurs.
Check for noises with the vehicle stopped, but with the engine running.
Determine if the noise occurs while the vehicle operates in the following:

•	Drive--Under a light acceleration or a heavy pull.

•	Float--Maintaining a constant speed with a light throttle on a level road.

•	Freewheel--With the transmission in gear and the throttle partly or fully closed.

•	All of the above

Checking Bearing Noise

Differential Side Bearing Noise

Differential side bearing noise and wheel bearing noise can be confused easily. Since side bearings are pre-loaded, a differential side bearing noise should not diminish much when the differential/transmission is run with the wheels off the ground.

Wheel Bearing Noise

Wheel bearings produce a rough growl or grating sound that will continue when the vehicle is freewheeling and the transmission is in NEUTRAL. Since wheel bearings are not pre-loaded, a wheel bearing noise should diminish considerably when the wheels are off the ground.

Checks	Actions
Insufficient Lubricant	Supply the lubricant.
Worn Input Shaft Gear	Replace the gear.
Worn Bearings on the Input Shaft Gears	Replace the bearing.
Worn Clutch Release Bearing	Replace the clutch release bearing.
Worn Bearings on the Input Shaft or Layshaft	Replace the bearing.
Worn Input Shaft or Layshaft Gear	Replace the gear.
Worn or Damaged Synchroniser Ring	Replace the synchroniser ring.
Worn or Damaged Synchroniser Sleeve	Replace the synchroniser sleeve.
Worn Differential Gear or Bearing	Replace the gear or bearing.
Worn or Damaged Synchroniser Ring in the selected Gear Range	Replace the synchroniser ring.
Worn or Damaged Gear in the selected Gear Range	Replace the gear.
Worn or Damaged Bearing in the selected Gear Range	Replace the bearing.