Typical Transmission Faults and Possible Causes
| SYMPTOM | POSSIBLE CAUSES |
| Knocking at low speed | Worn inner or outer constant velocity joint. (CV joint). Worn bearing seats. differential |
| Increased noise when driving through a turn |
Differential gear noise |
| Knocking during acceleration and deceleration of the vehicle |
Loose engine mounts. Worn inner CV joint. Wear of pinion shaft and bores in the differential case. Worn bearing seats. differential |
| Knocking when driving through a turn | Worn outer CV joint |
| Vibration | Bearing vibration. Bent axle shaft. Tire out-of-round. Wheel imbalance. Worn axle shaft CV joint. Excessive angles in CV joint (violation of suspension static travel) |
| Gears jumping out of mesh | Worn or misadjusted shift drive. gear shifting. Binding of the gear shift drive. Broken or loose retaining washers. input shaft bearings. Worn or deformed shift fork |
| Increased noise in neutral with the transmission running of the engine at idle |
Worn gear block bearings. input shaft. Worn clutch release bearing. Worn input shaft gears. Worn 1st gear or bearing. Worn 2nd gear or bearing. Worn 3rd gear or bearing. Worn 4th gear or bearing. Worn 5th gear or bearing. Worn output shaft bearings |
| Excessive noise only in 1st. gear |
Breakage, chipped teeth or wear of 1st gear. Wear of 1st and 2nd gear synchronizer. Worn 1st gear or bearing. Wear of gears or bearings. differential. Wear of final drive driven gear. Wear of shift lever and shift rod mechanism. shift |
| Excessive noise only in 2nd. gear |
Breakage, chipped teeth or wear of 2nd gear. Wear of 1st and 2nd gear synchronizer. Worn 2nd gear or bearing. Wear of gears or bearings. differential. Wear of final drive driven gear. Wear of shift lever and shift rod mechanism. shift |
| Excessive noise only in 3rd. gear |
Breakage, chipped teeth or wear of 3rd gear. gear. Wear of 3rd and 4th gear synchronizer. Worn 3rd gear or bearing. Wear of gears or bearings. differential. Wear of final drive driven gear. Wear of shift lever and shift rod mechanism. shift |
| Excessive noise only in 4th gear. gear |
Wear of 3rd and 4th gear synchronizer. Breakage, chipped teeth or wear of 4th gear. gear. Worn 4th gear or bearing. Wear of gears or bearings. differential. Wear of final drive driven gear. Wear of shift lever and shift rod mechanism. shift |
| Excessive noise only in 5th gear. gear |
Wear of 5th gear synchronizer. Breakage, chipped teeth or wear of 5th gear. gear. Worn 5th gear or bearing. Worn 5th gear or bearing. Wear of final drive driven gear. Wear of shift lever and shift rod mechanism. shift |
| Excessive noise only in reverse gear |
Breakage, chipped teeth or wear of reverse idler gear gear, wear of input and output shaft gears. shafts. Wear of 1st and 2nd gear synchronizer. Wear of final drive pinion gear. Wear of final drive driven gear. Wear of gears or bearings. differential |
| Excessive noise in all gears |
Insufficient oil level. Wear of bearings. Breakage, chipped teeth or wear of gears. Wear of input and/or output shafts or wear shafts. |
| Oil leakage in the area of clutch pedal |
transmission case. Clutch release bearing lever |
| Oil leakage in the middle of transmission case. |
transmission case. Shift mechanism. Back-up light switch. |
| Oil leakage on left side. of transmission case. |
Case cover. |
| Oil leakage from final drive | Final drive bearing caps and seal. gear. Final drive pan. Final drive pan |
| Gear grinding when engaging. gears. |
Clutch release bearing lever. Clutch release linkage. Input shaft or gear cluster. 5th gear synchronizer. 5th gear or bearing. 1st gear or bearing. 1st and 2nd gear synchronizer. 2nd gear or bearing. 3rd gear or bearing. 3rd and 4th gear synchronizer. 4th gear or bearing. Reverse gear. |
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