Manual Transmission Troubleshooting

Knocking noises occur at low engine speed
1 Worn driveshaft CV joint(s) (refer to Chapter Clutch and Driveshafts).
2 Worn driveshaft seat bore in the transaxle differential case (refer to Chapter Manual Transmission).

Slight grinding noise occurs during turns
Normal noises associated with differential operation (refer to Chapter Manual Transmission).

Dull metallic knocking noise occurs during engine acceleration or deceleration
1 Loose engine mount bracket bolts (refer to Chapters Engine and Manual Transmission).
2 Worn differential pinion shaft.
3 Worn driveshaft seat bore in the transaxle differential case (refer to Chapter Manual Transmission).
4 Worn or damaged inner driveshaft CV joint(s) (refer to Chapter Clutch and Driveshafts).

Metallic grinding noise occurs during turns
Worn or damaged outer CV joint on the inner (turning radius) driveshaft (refer to Chapter Clutch and Driveshafts).

Vibrations occur
1 Worn wheel bearings (refer to Chapters Maintenance and Adjustments and Suspension and Steering).
2 Damaged driveshaft (refer to Chapter Clutch and Driveshafts).
3 Deformed tires/unbalanced wheels (refer to Chapters Maintenance and Adjustments and Suspension and Steering).
4 Worn CV joints (refer to Chapter Clutch and Driveshafts).
5 Low transmission fluid level (refer to Chapter Maintenance and Adjustments).

Transmission noises with engine running in neutral
1 Worn input shaft bearings (noise occurs when the clutch pedal is released and disappears when it is depressed) (refer to Chapter Manual Transmission).
2 Worn clutch release bearing (noise occurs when the clutch pedal is depressed and may decrease when it is released) (refer to Chapter Clutch and Driveshafts).

Noises occur in one specific gear
1 Worn, chipped or otherwise damaged transmission gear teeth (refer to Chapter Manual Transmission).
2 Worn or damaged synchronizers (refer to Chapter Manual Transmission).
3 Bent reverse shift fork (refer to Chapter Manual Transmission).
4 Damaged fourth gear or output gear (refer to Chapter Manual Transmission).
5 Worn or damaged reverse idler gear or idler bushing (refer to Chapter Manual Transmission).

Noises occur in all gears
1 Low transmission fluid level (refer to Chapter Manual Transmission).
2 Worn or damaged bearings (refer to Chapter Manual Transmission).
3 Worn or damaged input and/or output shaft (refer to Chapter Manual Transmission).

Transmission jumps out of selected gear
1 Worn linkage rod or incorrect linkage adjustment (refer to Chapter Manual Transmission).
2 Loose transaxle-to-engine mounting bolts (refer to Chapter Manual Transmission).
3 Malfunctioning shift linkage rods (refer to Chapter Manual Transmission).
4 Broken input gear bearing retainer or loose retainer bolts (refer to Chapter Manual Transmission).
5 Dirt between clutch cover and engine block (refer to Chapter Manual Transmission).
6 Worn synchronizer assemblies (refer to Chapter Manual Transmission).
7 Worn shift forks (refer to Chapter Manual Transmission).

Difficult gear shifting
1 Faulty clutch (refer to Chapter Clutch and Driveshafts).
2 Worn or damaged shift mechanism components (refer to Chapter Manual Transmission).
3 Worn synchronizer assemblies (refer to Chapter Manual Transmission).

Transmission fluid leaks
1 Damaged differential output seal (refer to Chapter Manual Transmission).
2 Transmission overfilled with fluid (refer to Chapter Maintenance and Adjustments and Chapter Manual Transmission).
3 Broken input gear bearing retainer or loose retainer bolts (refer to Chapter Manual Transmission).
4 Damaged input gear bearing retainer O-ring and/or seal lip (refer to Chapter Manual Transmission).

Transmission locks in one of the gears
1 Detent pin or intermediate detent plunger has come out (refer to Chapter Manual Transmission).
Although repair of these faults is beyond the skill of the average do-it-yourself mechanic, this information will be useful when communicating with a professional.