How much does a differential pinion seal replacement cost?

What is a differential pinion seal?

The differential is driven from the engine and transmission via a driveshaft that bolts to the pinion mating surface.

As this surface is on the outside of the differential housing, a pinion seal is employed to precisely fit to stop any oil leaking out from the differential and to prevent any contaminants entering the sensitive internals.

A thin spring on the inside of the seal keeps tension on the seal which prevents oil leaking past. Poor oil condition can be harsh on the seal and, once a leak develops, this seal will need to be replaced.

Symptoms your differential pinion seal requires replacement

• Oil leaking from the pinion seal
• Low diff fluid levels
• Whining noise while driving

How is the differential pinion seal replaced?

• The technician inspects the vehicle to find the source of the leak
• The car is jacked up to allow access underneath
• The rear of the driveshaft is unbolted from the differential
• The pinion nut is marked and loosened, and the old seal removed
• The area is cleaned and the new seal fitted
• The driveshaft is reattached and the differential oil is checked and topped up
• The vehicle is lowered down and test driven to ensure correct operation

Tips to remember

• Some 4WD vehicles will have front and rear pinion seals, so both need to be inspected to ensure the correct seal is being replaced
• It is best practice to replace the differential fluid at the same time as replacing the seal

How important is replacing the differential pinion seal?

Having a differential that is operating correctly is imperative to proper operation of your vehicle.

If the differential fluid is low, increased wear or even complete differential failure can occur leaving you stranded at the side of the road.

Replacing a differential pinion seal that is leaking will help combat these types of failures and keep you happily motoring.