Initial Inspection and Diagnostic Overview

DRIVELINE SYSTEM INSPECTION/VERIFICATION

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical damage.





3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. If the cause is not visually evident, verify the symptom and GO to Symptom Chart in this procedure.

Driveshaft Center U-Joint and Constant Velocity (CV) Joint Inspection

With the vehicle in NEUTRAL, position it on a hoist. See Lifting. Rotate the driveshaft by hand. Check for rough operation or seizure of the U-joints or CV joints. Install a new driveshaft if it shows signs of seizure, excessive wear or incorrect seating. See Removal and Replacement.

Driveshaft Center Bearing

With the vehicle in NEUTRAL, position it on a hoist. See Lifting. Rotate the driveshaft by hand. If the bearing shows signs of roughness or is noisy, install a new driveshaft. See Removal and Replacement.

Analysis of Leakage

Clean up the leaking area enough to identify the exact source.
A plugged rear drive unit (RDU) housing vent can cause excessive pinion seal lip wear due to internal pressure buildup.
Verify the RDU lubricant level is at least 3-5 mm (1/8-3/16 in) below the bottom of the fill hole.

Axle Vent

A plugged vent will cause excessive seal lip wear due to internal pressure buildup. If a leak occurs, check the vent. If the vent cannot be cleared, install a new vent.

Drive Pinion Seal

Leaks at the drive pinion seal originate for the following reasons:

- Damaged seal
- Worn seal journal surface

Any damage to the seal bore (dings, dents, gouges or other imperfections) distorts the seal casing and allows leakage past the outer edge of the drive pinion seal.
The drive pinion seal can be torn, cut or gouged if it is not installed correctly. The spring that holds the drive pinion seal against the pinion flange may be knocked out and allow fluid to pass the lip.
Metal chips trapped at the sealing lip can cause oil leaks. These can cause a wear groove on the drive pinion flange and result in pinion seal wear.
When a seal leak occurs, install a new drive pinion seal and check the vent to make sure it is clean and free of foreign material.
A new drive pinion flange must be installed if any of these conditions exist.

Drive Pinion Nut

CAUTION: Install the drive pinion nut to the correct torque specifications or damage to the differential components may occur.
On some high-mileage vehicles, oil may leak through the threads of the drive pinion nut. This condition can be corrected by installing a new nut and applying threadlock and sealer on the threads and nut face.

Differential Seals

CAUTION: When installing halfshafts, do not allow splines to contact seals during installation or damage to the seals may occur.
Halfshaft pilot bearing housing seals are susceptible to the same types of damage as drive pinion seals if incorrectly installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. The seal journal surface must be free of nicks, gouges and rough surface texture.
For additional information on differential seals, See Stub Shaft Pilot Bearing And Seal Removal/Installation.