Your driveshaft spins a pinion that is connected to your differential. The differential is geared and spins your wheels a certain speed given the speed of the driveshaft rotation. The differential has a very important job, the pinion seal makes sure nothing interferes with this job. 

What is a differential pinion seal?

It’s much like all the other seals on your car. It’s a hard synthetic rubber seal that keeps your differential oil inside the differential and contaminants out. It has a metal casing that keeps it in place and a spring that helps it hold its shape.

Why do you need a differential pinion seal?

If the seal cracks or starts to leak differential oil it can lead to contamination inside the differential housing. This results in damage to the gears inside the diff and that can lead to serious repair bills.

How to tell if you need a new differential pinion seal

If you notice the differential leaking gear oil then that’s an obvious indication. Other indications are a grinding noise from the back of the car. If the service interval comes up then it will generally get replaced when the differential oil is replaced.

What’s involved in getting a differential pinion seal replaced?

The mechanic will unbolt the driveshaft from the pinion and support it while working on the differential. They will then unbolt the pinion and remove the seal while draining the gear oil. The differential will be checked and the new pinion seal will be fitted. The gear oil will be refilled and the driveshaft rebolted. The car will be test driven to make sure everything is working as it should.

How much does a differential pinion seal replacement cost near Ashburton?

Given that the driveshaft needs to be unbolted and the diff oil drained, the costs start around $220 and can go above $350 for the replacement.

How often do I need a differential pinion seal replaced?

Only as your mechanic tells you. Generally speaking, the pinion seal is often replaced when the differential oil is changed, so you won’t have to worry too much. 

Is a broken differential pinion seal unsafe?

It can lead to painful repair costs to fix your differential. These are best avoided so if it needs replacing you should get it replaced.

You can find a mechanic near Ashburton with My Auto Shop