Spurred on by mhadden's great thread on changing the oil, (and thanks to daless2 for some additional info) here is a "how-to" for changing your rear differential fluid.
Supplies Needed:
4 quarts of gear oil. Toyota calls for the following spec on the Differential Fluid = LT 75W-85 - GL-5 rated but 75w-90 will do. I chose Royal Purple because it comes with the no-slip additive already in it. How much Differential fluid you will actually use depends on what model truck you have, RC, DC, CC, and if it is 2 or 4 wheel drive.
In all cases it will be between 3.6 and 4.0 quarts.
15/16" socket.
A way to get the driver's side of the vehicle up so all the fluid drains out. The safest way would be to use one of the metal ramps and drive up on it. If you plan on using the truck's jack, you will need 2 bricks so you can get it high enough. More on that later, but you know you should never work under a truck supported by just a jack, right?
Towels.
Oil catch pan.
A warmed-up truck. Drive around and get the truck to normal operating temperature. Park on a level surface, wait about 10 minutes, then begin.
STEP 1:
(If you're going to use one ramp on the driver's side, drive on that now before you empty your oil out. If you're going to use a jack, wait to do so because the force of you loosening the bolts may make a dangerous situation even more dangerous)
Loosen the FILL BOLT. Always loosen the fill bolt first. What if you loosened the drain bolt first and then couldn't loosen the fill bolt? You'd be empty and out of service. Put the fill bolt somewhere you won't lose it.
STEP 2:
Place your oil catch pan underneath the DRAIN BOLT.
STEP 3:
Loosen the drain bolt and allow the oil to drain out. Give it some time to drain properly.
STEP 4:
Inspect and clean your DRAIN BOLT. It is magnetized. At 1000 miles on my truck it had a bulbous gel-like goo that was black and full of shavings. Clean that all off and place somewhere you won't lose it.
STEP 5:
Jack up the truck so all of the oil can drain out. I used two bricks since the stock jack isn't long enough. Notice I said do this now because if you do it first, using a lot of force to loosen the bolts could topple the truck. NEVER WORK UNDER A TRUCK THAT'S ONLY SUPPORTED BY A JACK. It isn't safe.
STEP 6:
Screw back in your DRAIN BOLT. Hand-tighten and then use the ratchet.
STEP 7:
Fill up the differential until it comes out of the fill hole. Tighten the fill nut by hand then use the ratchet.
Torque Settings
The Fill Plug has a torque setting of 36 Ft/#’s
The Drain Plug torque setting is 29 Ft/#’s
Toyota does recommend installing a new gasket on each of these plugs. I doubt you will have to however.
STEP 8:
Clean up and go find an open parking lot and do a bunch of figure eights. This is to get the gear oil to all the parts.
STEP 9:
Park on an even surface, unscrew the fill bolt again and check the level. Top off if need be. Replace the fill bolt and you're done.
I hope this helps. I take no responsibility for any damages to you or your truck for following this. I suggest you always take your truck to an authorized Toyota dealer for service. Thank you.
Linear Mode
