All Previa van transfer cases use Grade GL-4 or GL-5 with the viscosity of SAE75W-90 gear oil.
See Figures 1, 2 and 3
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.
- 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.
- 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.
- Replace the filler plug and tighten it to 29 ft. lbs. (39 Nm). Run the engine and check for leaks.
DRAIN & REFILL
See Figures 4 through 9
Once every 30,000 miles (48,000 km), the oil in the transfer case should be changed.
- The transfer case oil should be hot before it is drained. If the engine is at normal operating temperature, the oil should be hot enough.
- Raise the van and support it properly on jackstands so that you can safely work underneath. You will probably not have enough room to work if the van is not raised.
- Remove the filler plug from the side of the case. There will be a gasket underneath this plug. Replace it if damaged.
- The drain plug is located on the bottom of the transfer case. Place a pan under the drain plug and remove it. Keep a slight inward pressure on the plug while unscrewing it, this will keep the oil from pouring out until the plug is removed.
- Allow the oil to drain completely. Clean off the plug and replace it, tightening it until it is just snug 29 ft. lbs. (39 Nm).
- Fill the transfer case with gear oil through the filler plug hole as detailed previously. Refer to the Capacities chart for the amount of oil needed to refill your transfer case.
- The oil level should come right up to the edge of the hole. You can stick your finger in to verify this. Watch out for sharp threads.
- Replace the filler plug and gasket, tighten to 29 ft. lbs. (39 Nm), lower the van, and check for leaks. Dispose of the old oil in the proper manner.