GM Prizm/Nova 1985-1993 Repair Guide

A13L 3-Speed Automatic Transaxle Differential (Final Drive Unit)



The correct automatic transmission differential fluid for all Nova and Prizm cars is Dexron® II. There are no acceptable substitutes; internal damage may result if other fluids are used.


See Figure 1

The oil in the differential should be checked at least every 5,000 miles and replaced every 20,000 miles.

  1. With the car parked on a level surface, remove the filler plug from the SIDE of the differential.

The plug on the bottom of the differential is the drain plug. Do not confuse the differential filler plug with the filler plug for the transaxle.

  1. If the lubricant begins to trickle out of the hole, there is enough lubricant. Otherwise, carefully insert your finger (watch out for sharp threads) and check to see if the oil is up to the edge of the hole.

Used oil may cause skin cancer if repeatedly left in contact with the skin for prolonged periods. Although this is unlikely unless you handle oil on a daily basis, it is wise to thoroughly wash your hands with soap and water immediately after handling used oil.

  1. If the oil is not up to level, add oil through the hole until the level is at the edge of the hole. Most gear lubricants come in a plastic squeeze bottle with a nozzle, making additions simple. The differential uses Dexron® II automatic transmission fluid.
  3. Replace the filler plug, run the engine and check for leaks.

Click image to see an enlarged view

Fig. Fig. 1: Filler and drain plug locations on the front differential


The fluid in the differential should be changed at least every 20,000 miles.To drain and fill the differential, proceed as follows:

  1. Park the vehicle on a level surface. Set the parking brake.
  3. Remove the filler (upper) plug. Place a container which is large enough to catch all of the differential fluid under the drain plug.
  5. Remove the drain (lower) plug and allow all of the oil to drain into the container.
  7. Install the drain plug. Tighten it so that it will not leak, but do not overtighten.
  9. Refill with 1.5 quarts of Dexron® II automatic transmission fluid. Be sure that the level reaches the bottom of the filler plug.
  11. Replace the filler plug, run the engine and check for leaks.

Please dispose of used oil properly. Do not throw it in the trash or pour it on the ground. Take it to your dealer or local service station for recycling.