Differential Service

Step by step guide on how to service an automotive differential. This is a general guide that covers most vehicles.

Difficulty Rating: 2 of 10

Tools and supplies Needed

  • Socket and ratchet set
  • Gasket scraper
  • Screw driver
  • Differential cover gasket
  • Gear oil
  • Shop towels
  • Safety eyewear and gloves
Begin by parking the car and level ground, blocking both front wheels to prevent movement. Also put the transmission in park, with the emergency brake set. Even though the rear wheels will be in the air and will not help the vehicle from moving its a good safety habit.

Step 1 - After the vehicle is safely lifted into the air enough to be able to work on the differential, start by locating the service cover or drain port of the differential. Some differentials utilize a drain plug which can be simply removed to allow the gear oil to drain out. Unfortunately most vehicles are designed with a rear cover that must be removed to allow gear oil drainage. To remove the cover position a liquid drain basin directly under the cover and start removing the cover bolts. While removing the bolts allow the bottom three bolts to be loosened only, this will help support the cover once the remainder of the bolts have been removed.

Differential Cover

Step 2 - Once all other bolts have been removed use a screw driver to help separate the cover from the differential housing. Once the seal has been broken gear oil will start to flow out. (Note: position a oil drain catch basin under the differential cover.)

Draining Differential Fluid (Gear Oil)

Step 3 - Continue this operation until the stream of gear oil has stopped, then remove the remaining three cover bolts while holding the cover in place. Once the bolts have been removed allow the cover to fall away from the housing to expose the inner workings.

Removing the Differential Cover

Step 4 - Once removed clean the cover by scraping the gasket from the cover surface, also wipe out the cover while cleaning the particle magnet.

Metal Shaving in Differential


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-07)