How to Perform a Differential Flush on Your Car

The differential is a vital part of every vehicle and it's easy to forget to replace the differential oil. This is how you do it.

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Introduction

Differentials are part of the drive train of a vehicle. They use internal gears to alter the direction of driveshaft rotation and to gear down the drive train. All differentials contain oil that needs to be changed every 30,000 to 60,000 miles. With a service interval that long, it's easy to forget.

Here's how to do the job yourself and extend the life of your vehicle. Having a differential flush done professionally will cost anywhere from $90 to $150. Materials to do the job yourself, as shown in the following steps, cost less than $30 and the process will take about an hour.

Tools Required

  • Cleaning brush
  • Drain pan
  • Jack & jack stands (optional)
  • Wrench to remove drain plug bolt or cover bolts

Materials Required

  • Differential cover gasket or gasket maker caulking
  • Differential oil (typically 80W90 grade; check your manual)

Project step-by-step (7)

Step 1

Raise the Vehicle or Block the Wheels

This step is only necessary when vehicle ground clearance is insufficient.

  • Park the vehicle on a flat, level, hard surface.
  • Jack up the vehicle.
  • Place jack stands under the vehicle as needed to raise it enough to work underneath.
  • Block the wheels and remove the keys if you’re working without jacking and jack stands.

Block the WheelsSteve Maxwell for Family Handyman

Step 2

Drain the Differential

  • Brush off the differential housing to remove dust and road dirt.
  • Place a drain pan under the differential to catch old oil.
  • Remove the drain plug or differential cover bolts and cover.
  • Allow the differential to drain for 30 minutes in warm weather or two hours if temperatures are below 50 degrees F.
  • Take the waste oil to an auto garage or a toxic waste facility for safe disposal. The garage where I take my waste oil uses it to heat the shop in winter using a special waste oil furnace.
    • This step can vary a lot depending on your vehicle design. Some differentials have drain plugs that allow old oil to flow out of a single hole, while other designs require multiple bolts be removed and a cover taken off to let out the oil. The vehicle shown here has a cover-type differential. Look online or refer to a maintenance manual for details on your particular vehicle.

Drain the DifferentialSteve Maxwell for Family Handyman