How to Change the Rear End Fluid

Inside the rear differential of rear-wheel- and all-wheel drive vehicles sits a network of gears protected by heavy-weight oil. Heat builds within the differential while you are driving. The heat causes the oil to break down and lose its protective qualities. Allowing broken-down oil to remain in the rear will cause the internal gears to wear, especially when the vehicle starts or when the transmission shifts. Changing the differential oil at regular intervals keeps the internal gears protected.

• 1

  Secure the vehicle by applying the parking brake.

• 2

  Slide an oil pan under the differential housing, located in the center of the vehicle's rear. Allow the vehicle to sit for three to four hours if the vehicle is hot.

• 3

  Turn the lower drain bolt counterclockwise with a socket attached to a 3/8-inch ratchet handle. Remove the loosened bolt from the differential. The fluid will start to flow from the rear. Allow all the oil to drain from the rear. Install the bolt back in the differential housing.

• 4

  Remove the oil fill plug---located higher on differential housing---by turning it counterclockwise with the socket and ratchet handle.

• 5

  Twist the lid off a can of differential oil by turning it counterclockwise by hand. Attach an oil pump to the opening of the oil can.

• 6

  Push the hose of the oil pump into the oil fill opening. Pump the handle of the oil pump to fill the rear with oil. Stop filling when oil seeps from the fill hole.

• 7

  Thread the oil filler plug in the opening of the rear end. Tighten the bolt with the socket and ratchet handle.