Noisy Operation
Transmission noise is most often a result of:
- Worn or damaged internal components
- Chipped, broken gear or synchronizer teeth, and damaged bearings
- Insufficient lubricant
- Aftermarket additives can damage synchronizers
NOISE IN NEUTRAL
With the vehicle stationary, transmission in neutral, engine running, there is a noise at high frequency and low intensity in the transmission area.
| PRELIMINARY CHECKS | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
|---|---|---|---|
| 1. Visually check if the noise is accompanied by an oil leak from the gearbox / differential. 2. Depress the clutch pedal and observe if the noise increases or decreases. 3. Check the oil level in the gearbox. |
Continue to next step | 1. Oil leak from the gearbox 2. With the clutch depressed: if the noise disappears it is most likely internal transmission noise. If the noise increases it is most likely clutch, dual mass flywheel, or the clutch release bearing. 3. Oil level too low |
1. Repair leak and fill transmission to proper fluid level. 2. Remove transmission and replace damaged components. 3. Correct the transmission oil level and perform a road test. Refer to FLUID, STANDARD PROCEDURE . If the fault persists, go to Step 2. |
| CHECK CLUTCH DISC SPLINES | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
| Check for the presence of excess wear on splines of the clutch disc and transmission input shaft. | Continue to next step | Worn or damaged input shaft splines and worn or damaged splines in the clutch disc. | Replace the transmission input shaft and clutch disc. Refer to DISC, CLUTCH, REMOVAL AND INSTALLATION . |
| Check the transmission dowel pin hole for damage. | Replace clutch disc and transmission. | Transmission and clutch disk shaft are misaligned. | Replace clutch disc and transmission. Refer to DISC, CLUTCH, REMOVAL AND INSTALLATION . |
| CHECK SHIFTER CABLE HARDWARE | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
| Check for any obstruction of the shifter. Check the routing of the shifter cables, the attachment to the transmission and the shifter, and shifter cable adjustment. | Continue to next step | Cables not properly fitted Cables not properly adjusted |
Remove any gear shifter obstructions. Restore the proper routing and attachment of the shifter cables. Refer to CABLE, GEARSHIFT CONTROL, REMOVAL AND INSTALLATION . Re-adjust the shifter cables. Refer to CABLE, GEARSHIFT CONTROL, ADJUSTMENTS . |
| CHECK CLUTCH DISC | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
| Inspection: Wear of the clutch disc Contamination (oil or grease) of the clutch disc Deformation of the clutch disc Damage to the diaphragm spring pressure plate |
End diagnosis | 1. Worn or damaged clutch disc or pressure plate 2. Presence of oil or grease |
1. Replace the clutch disc and pressure plate Refer to DISC, CLUTCH, REMOVAL AND INSTALLATION
. 2. Also, replace the transmission input shaft seal |
NOISE WHILE SHIFTING
While driving, a noise is heard in a specific gear from the transmission area. The noise stops when shifted to a different gear.
| CHECK THE SYNCHRONIZERS | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
|---|---|---|---|
| Remove and disassemble transmission to inspect the appropriate synchronizer(s). | Continue to next step | Worn or damaged synchronizer components | Replace worn components as necessary. |
| CHECK THE GEARS | EVERYTHING OK | PROBLEMS ENCOUNTERED | RESOLUTION |
| Remove and disassemble transmission to inspect the appropriate gear(s). | End diagnosis | Worn or damaged gears | Replace the gear(s) as necessary. |