The oil in the transfer case should be checked at least every 15,000 miles (24,000 km) and replaced every 25,000–30,000 miles (40,000–48,000 km), even more frequently if driven in deep water.
- With the van parked on a level surface, remove the filler plug from the transfer case housing. the filler plug is the higher of the two plugs on the unit.
| Fig. 1:
Remove the filler plug with gasket . . .

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- If the lubricant begins to trickle out of the hole, there is enough. 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.
| Fig. 2:
. . . then use your finger to check the level of the transfer case fluid

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- If not, 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.
| Fig. 3:
Add gear oil through the transfer case fill plug

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- Replace the filler plug and tighten it to 29 ft. lbs. (39 Nm). Run the engine and check for leaks.