For 1990-2009 cars

Differential oil leaks can occur at the following locations:

• | Axle shaft seals.

• | Pinion flange oil seal.

• | Differential housing porosity.

• | Differential housing front to rear cover joint seal.

• | Drain plug and/or O-ring

• | Fill plug and/or O-ring

• | Vent tube

### Determining the Cause

While most differential oil leaks may be easy to find, determining the cause may not be. A thorough inspection of the area around the leak may assist in determining the cause of the oil leak.

#### Oil Seals

Lubricant leaks from an oil seal may be caused by any of the following:

• | An incorrectly installed seal.

• | A distorted or damaged seal.

• | A worn seal.

• | A worn shaft.

• | A brittle seal lip.

• | A hardened seal lip.

• | Foreign material in oil.

• | Distorted or damaged slinger on wheel drive shaft.

To determine the actual cause of the leak, clean the area around the leak. Observe the area of the leak and determine if the seal or another component is causing the leak. A worn seal surface will cause a leak at the sealing lip while a misaligned seal or a seal installed into a housing with an excessive bore will cause the seal to leak at the outside surface of the seal. Hardened or cracked seal lips usually indicate the rear drive axle is operating beyond the normal temperature limits for the rear drive axle. A seal whose sealing surface has been nicked or cut may indicate that the shaft has a rough, burred, or gouged surface and will need to be inspected before the seal can be replaced.

#### Differential Housing

Differential housing lubricant leaks usually occur at the following locations:

• | Drain plug and/or O-ring.

• | Fill plug and/or O-ring.

Drain and fill plug leaks are usually caused by a loose plug or damaged O-ring. These leaks can by repaired by either tightening the plug to the specified torque or replacing the drain or fill plug which comes with a new O-ring. Other leaks are usually from the join between the front and rear housing which uses loctite as a sealant. In this case the differential must be removed and re-sealed and tested.