Transfer Case

The 4–wheel drive family of vehicles use a transfer case between the transmission and the driveshaft. This case contains a series of gears and chains which must be properly lubricated. Although the transfer case is connected to the transmission, the two units have separate oil supplies. Do not make the mistake of thinking that draining or filling one unit takes care of both.

The transfer case has a drain plug at the lower edge and a fill plug about halfway up the case. Fluid level is checked with the vehicle parked on a level surface and the wheels blocked. It may be necessary to raise and support the vehicle on jackstands to access the drain and fill plugs on the transfer case. Remove the filler plug. If the fluid runs out of the hole, the level is okay and you can immediately reinstall it. If fluid does not run out, you can stick your finger into the hole to check the level. As long as it is at or near the level of the bottom of the hole (no more than about ¹⁄₄ inch below) the level is ok. If necessary, add API GL-4 fluid of viscosity SAE 80W or SAE 75W–85W. This fluid specification does not change if the vehicle is equipped with an automatic transmission. To drain the fluid follow the service procedure below.

1. Park the vehicle on a level surface.
2. It may be necessary to raise and support the vehicle on jackstands to access the drain plug on the transmission.
3. Position a suitable drain pan under the transfer case drain plug and remove the fill plug.
4. Remove the drain plug and allow the oil to drain completely.
5. Wipe off the threads of the drain plug and install the plug with a new gasket.
6. Through the filler plug opening, add fluid (API GL-4, SAE 80W or SAE 75W–85W) until the level is just below the bottom of the opening. If a small amount runs out, that's OK.
7. After wiping the threads, install and tighten the filler plug.
8. Drive the vehicle to allow the oil to reach operating temperature and then check the drain, fill plugs for leaks.