Driveline Snap
WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
A snap or clunk noise when the vehicle is shifted into gear, can be caused by:
- High engine idle speed.
- Transmission shift operation.
- Loose engine/transmission/transfer case mounts.
- Worn U-joints or CV joints.
- Worn or broken axle mount isolators.
- Loose pinion gear nut and yoke.
- Excessive ring gear backlash.
- Excessive side gear to case clearance.
The source of a snap or a clunk noise can be determined with the assistance of a helper. Raise the vehicle on a hoist with the wheels free to rotate. Instruct the helper to shift the transmission into gear. Listen for the noise, a mechanics stethoscope is helpful in isolating the source of a noise.
DIAGNOSTIC CHART
| CONDITION | POSSIBLE CAUSE | CORRECTION |
|---|---|---|
| WHEEL NOISE | 1. Wheel loose. | 1. Tighten loose nuts. |
| 2. Faulty, brinelled wheel bearing. | 2. Replace bearing. | |
| DIFFERENTIAL CRACKED | 1. Improper differential side bearing preload. | 1. Replace case and inspect gears and bearings for further damage. Set differential bearing preload properly. |
| 2. Excessive ring gear backlash. | 2. Replace case and inspect gears and bearings for further damage. Set ring gear backlash properly. | |
| 3. Vehicle overloaded. | 3. Replace case and inspect gears and bearings for further damage. Avoid excessive vehicle weight. | |
| DIFFERENTIAL GEARS SCORED | 1. Insufficient lubrication. | 1. Replace scored gears. Fill differential with the correct fluid type and quantity. |
| 2. Improper grade of lubricant. | 2. Replace scored gears. Fill differential with the proper fluid type and quantity. | |
| 3. Excessive spinning of one wheel/tire. | 3. Replace scored gears. Inspect all gears, pinion bores, and shaft for damage. Service as necessary. | |
| LOSS OF LUBRICANT | 1. Lubricant level too high. | 1. Drain lubricant to the correct level. |
| 2. Worn axle shaft seals. | 2. Replace seals. | |
| 3. Cracked axle housing. | 3. Repair as necessary. | |
| 4. Worn pinion seal. | 4. Replace seal. | |
| 5. Worn/scored pinion flange journal. | 5. Replace pinion flange and seal. | |
| 6. Axle cover not properly sealed. | 6. Remove, clean, and re-seal cover. | |
| AXLE OVERHEATING | 1. Lubricant level low. | 1. Fill differential to correct level. |
| 2. Improper grade of lubricant. | 2. Fill differential with the correct fluid type and quantity. | |
| 3. Bearing preload too high. | 3. Readjust bearing pre-load. | |
| 4. Insufficient ring gear backlash. | 4. Re-adjust ring gear backlash. | |
| GEAR TEETH BROKE | 1. Overloading. | 1. Replace gears. Examine other gears and bearings for possible damage. |
| 2. Ice-spotted pavement. | 2. Replace gears and examine remaining parts for damage. | |
| 3. Improper adjustments. | 3. Replace gears and examine remaining parts for damage. Ensure ring gear backlash is correct. | |
| AXLE NOISE | 1. Insufficient lubricant. | 1. Fill axle with the correct fluid type and quantity. |
| 2. Improper ring gear and pinion adjustment. | 2. Check ring gear and pinion contact pattern. Adjust backlash or pinion depth. | |
| 3. Unmatched ring gear and pinion. | 3. Replace gears with a matched ring gear and pinion. | |
| 4. Worn teeth on ring gear and/or pinion. | 4. Replace ring gear and pinion. | |
| 5. Loose pinion bearings. | 5. Adjust pinion bearing pre-load. | |
| 6. Loose differential bearings. | 6. Adjust differential bearing preload. | |
| 7. Misaligned or sprung ring gear. | 7. Measure ring gear run-out. Replace components as necessary. | |
| 8. Housing not machined properly. | 8. Replace housing. |