The recommended oil for the transfer case is API-GL-5/SAE 80W, or equivalent.
There is a plug to the left side of the flange for the rear wheel driveshaft. The level is checked by removing this plug and checking the fluid level. The fluid should be no more than 1 / 2 inch (13mm) below this plug. If your finger is unable to fit in this opening, a small screwdriver works.
DRAIN & REFILL
The transfer case cannot be drained while still attached to the transmission. However, an alternative method is to use a hand-held vacuum pump with a piece of hose and suck out the fluid. Refill with the appropriate grade of oil.