The oil level in the differential should be checked every 15,000 miles (24,000) or 12 months, whichever comes first. The oil should be checked with the car on a level surface. Remove the oil filler and upper plug, located on the back of the differential.
The bottom plug is the drain.
The oil level should reach to the bottom edge of the filler hole. If low, replenish with API grade GL-4 or GL-5 gear oil of the proper viscosity. The viscosity is determined by the ambient temperature range. If the temperature averages above 10°F (-12°C), use SAE 90 gear oil. If the temperature averages below 10°F (-12°C), use SAE 80 oil. Always check for leaks when checking the oil level.
DRAIN & REFILL
- Park the vehicle on a level surface. Set the parking brake.
- Remove the filler (upper) plug. Place a container which is large enough to catch all of the differential oil, under the drain plug.
- Remove the drain (lower) plug and gasket, if so equipped. Allow all of the oil to drain into the container.
- Install the drain plug. Tighten it so that it will not leak, but do not over tighten.
- Refill with the proper grade and viscosity of axle lubricant. Be sure that the level reaches the bottom of the filler plug.
- Install the filler plug and check for leakage.