What are you going to need?
Title:Changing the differential fluid
Time: 2-3 hours Difficulty: 3/10
Vehicle: Nissan Xterra Author: Brent Scott


1/2" drive ratchet or breaker bar, with a short extension
5 quarts of 80W90 (75W90 will do) GL-5 gear lube (3 for rear only) (Rear is 5-7/8 pints, front is 3-1/8 pints, 9 pints total)
Large oil catch basin (recycle used oil at a garage or recycling center)
Toothpicks or other implement to remove gunk from threads without scratching or damaging the threads.
A rag you don't care about getting smelly oil on.
A hose that fits over the nozzle of the gear oil bottle, or some sort of pump, in order to reach the front diff fill hole. (hose should be too long to fall completely into the diff!)
4 oz. friction modifier additive for limited-slip differentials if the oil you are using is not LSD-compatible. Available from your
dealer or parts store. (Mobil 1 synth is LSD-compatible, but I understand Valvoline Synth is not)

Check your car manual for proper type of oil on your vehicle.

Optional items:

Metric socket to remove front sway bar.
Thread sealer:
Permatex #14A Thread Sealer w/ Teflon (part #80631)
or Permatex High Performance thread sealer (part #25117)
or equivalent. Teflon tape is not recommended.


none at this time
Changing the differential fluid on a Nissan Xterra

Important note: Do not open the drain plug of the differential without first verifying that you can open the fill plug. You do
not want to discover the fill plug is frozen after you have emptied the diff!

Rear differential:
Lower and remove the spare tire.
Open the fill plug.
Place catch basin under diff.
Open the drain plug and let the oil drain into the basin.
Inspect the drain plug for metallic "fuzz" and roughly note how much is present, take a picture if you like. This is for possible documentation of the classic "diff whine" problem should it ever arise. Some fuzz will bepresent regardless.
Wipe off the fuzz from the drain plug, and clean the threads of both plugs and holes with the toothpick, taking care not to break the toothpick into the differential housing.
If you are applying sealant, twist your rag into a point and shove a portion into the drain hole to wick up some of the remaining
oil. This is to lower the level a bit below the lip of the drain hole so the threads can be cleaned.
Wipe the threads of the drain hole and drain plug dry.
Completely fill the threads of the plug with sealant if you are using it.
Install the drain plug, tightening it firmly. Wipe
away excess sealant.
Add the proper amount of friction modifier if needed, then add 2 full quarts of oil. Continue adding oil in small increments, checking with your finger along the way, until the level is just below the bottom of the fill hole. (we want the threads to be oil-free if using sealant)
Clean the threads of the fill hole, wick excess oil with rag if needed.
Apply sealant to fill plug and install fill plug firmly.

Front differential:
Same as the rear, but the fill hole is hard to access. Removing the front sway bar may be helpful. You will need a short
extension to reach the plug regardless. When adding oil, 1 full quart may be added before you begin checking the level with
your finger.

That's it. Give any sealant some time to set up, then drive a while and check for leaks. Keep checking for leaks for a week or two to be safe.

Good luck,
Brent Scott


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