Rear Differential Fluid Replacement Basics

On the rear of an all-wheel drive car, is the differential that transfers power from the drive shaft to each wheel via a series of gears and axels. The interlocking ring and the pinion gears need specific lubrication to spin smoothly and send power efficiently. Below are the steps you’ll require to replace your rear differential fluid. You will need Socket and wretch, a catch can, break clean, gloves, glasses, gear oil, torque wrench, and a pump.

Refer to your owners manual to see what your service intervals are from the factory, and in there it will equally say what type of oil you should be putting in your rear differential. The car manual shouldinstructyou to remove the fill plug first, for two reasons. Number one, you want to ensure the plug has not seized, and would therefore keep you from refilling the new gear oil once the old is emptied, especially if this is your only vehicle. You would be stuck since you couldn’t move or drive the vehicle safely with no gear oil.

Now number two,when you do it so the oil can drain out a bit easier, but you do want to make sure no dirt gets in the exposed hole while it is draining. Some rear diffs do not have a drain plug like this one referred in this article, and need you to remove the cover itself. Contact your manual before you get started. This can become a complicated job. On this particularcar, changing the rear diff fluid is similar to changing engine oil. Remove the lower drain bolt and catch the fluid in a pan or a catch can.

The very last few turns of the bolt should be performed by hand so that you can stop dropping the bolt and magnet into the pan full of old oil. Ensure to properly dispose of the spent fluid, this is toxic and must be disposed of normally. Check your local auto parts store to see if they recycle or can recommend where to visit.

Next, Be sure to clean the bolt which doubles as a magnet. This is designed to catch the metal shavings produced by the gear’s rubbing during regular use, and is perfectly normal. Use brake clean and a clean rag to take out the debris before re-installing with the new crush washer. Hand tightens the bolt at first to avoid cross-threading, then torque to your manufacturer’s suggested torque spec. Next, the gear oil is retrieved from sitting outside in the sun. By heating it up in the sun, it flows a bit easier as it moves through the hose and into the pumpkin. Now put one end of the pump hose into the oil and the other end into the fill hole. Pump until suction is produced, and oil begins to move from the container. Bear in mind, if your vehicle has positraction or a limited slip differential; a special gear oil additive is required to keep those extra parts lubricated properly.

At the very least, read your owner’s manual to know the maintenance routine for all your car fluids, including the mostly forgotten rear differential.