DRAIN & REFILL

The manufacturer recommends that the transfer case fluid should be changed every 60,000 miles (96,000km). However, if the vehicle is driven in deep water (as high as the transfer case housing) it is a good idea to replace the fluid. Little harm can come from a fluid change when you have just purchased a used vehicle, especially since the condition of the transfer case fluid is usually not known.

If the fluid is to be drained, it is a good idea to warm the fluid first so it will flow better. This can be accomplished by 15–20 miles of highway driving. Fluid which is warmed to normal operating temperature will flow faster, drain more completely and remove more contaminants from the housing.

1. Drive the vehicle to assure the fluid is at normal operating temperature.
2. Raise and support the vehicle securely on jackstands. Remember that the vehicle must be supported level (usually at four points) so the proper amount of fluid can be added.
3. Place a drain pan under the transfer case housing, below the drain plug. Remember that the fluid will likely flow with some force at first (arcing outward from the transmission), and will not just drip straight downward into the pan. Position the drain pan accordingly and move it more directly beneath the drain plug as the flow slows to a trickle.

   NOTE: To insure that the fill plug is not frozen or rusted in place, remove it from the transfer case BEFORE removing the drain plug. It would be unfortunate to drain all of your transfer case fluid and then realize that the fill plug is stripped or frozen in place.

4. Remove the fill plug, the level plug (MPV models), then the drain plug and allow the transfer case fluid to drain out.

   Fig. 1: Verify that the oil level is near the filler or level plug port

   NOTE: On B Series Pick-up and Navajo models, the transfer case drain plug is usually a square receiver which is designed to accept a ³⁄₈ in. driver such as a ratchet or extension.

5. Once the transfer case has drained sufficiently, install the drain plug. For B Series Pick-up and Navajo models, apply sealant to the threads of the drain plug, then install. For MPV models, install the drain plug and new washer. Tighten the drain plug to 14–22 ft. lbs. (19–30 Nm) on B Series Pick-up/Navajo and 29–43 ft. lbs. (40–58 Nm) on MPV models.
6. Fill the transfer case to the proper level with the required fluid.
7. For B Series Pick-up and Navajo models, apply sealant to the threads of the filler plug and install. For MPV models, install the level and filler plugs along with new washers. Tighten the filler plug (B Series Pick-up/Navajo) or level plug (MPV) to 14–18 ft. lbs. (19–25 Nm). Tighten the filler plug (MPV) to 29–43 ft. lbs. (40–58 Nm).
8. Remove the jackstands and carefully lower the vehicle.