Changing Front and Rear Diffs and Xfer case-2005+ Tacoma (with pics)
I had been planning to put a detailed "how to" together on the front and rear diff and transfer case maintenance, and finally got around to finishing it up. There have been other posts containing bits and pieces of this information, but now hopefully this detailed step by step with pics pulls all of that together and will help some guys that are hesitant to give this a crack.
The rear diff is easier than an oil change. The front is only more difficult because of its location.
Added the transfer case write up with pics down below.
Materials:
- 6 quarts of 90 weight gear oil (I used Redline 75w-90ns for my TRD Off Road with Locker) for both diffs and the transfer case, or
3.0 quarts for rear diff
1.6 quarts for front diff
1.1 quarts for transfer case
- TRD Sport models and trucks with the mechanical LSD should use Redline 75w-90 (not the ns), as this contains the friction modifiers necessary for the LSD. If you are using a different fluid brand, just make sure it is formulated for LSD rear ends.
- 2 Crush washers for rear drain and fill plug
Part No:12157-10010 x 2
- 2 Crush washers for front drain and fill (larger copper washer is for front fill)
Part No: 12157-10010 x 1 and 90430-24003 (copper) x 1
-2 crush washers for transfer case drain and fill plug
Part no: 90430-18008 x 2 (05Moose: Latest part number is 90430-A0003)
- 10mm hex head socket for front drain and fill plugs
- 24mm socket for rear drain and fill plugs and transfer case plugs
- Torque wrench to tighten plugs to spec.
- 12mm socket (with 3” extension) to remove lower skid plate (not shown)
- Oil hand pump (shown later in action)
- Optional: Jack, Rubber mallet
This picture is for the front and rear diffs. Add another quart of oil and 2 more washers for the transfer case.
To get your truck ready for the fluid change, drive it around and get the engine warm and the gears moving. Return to your garage, and let the truck cool for about 15 minutes.
REAR DIFF
Loosen and remove the fill plug first using a 24mm socket (you don’t want to drain the old fluid out and then figure out the fill plug is stuck)
Then loosen and slowly remove the drain plug with the same 24mm socket, and let the old fluid drain into an oil pan.
I let it drain for a good 15-20 minutes. I also got my floor jack out and lifted the left side of the truck to help the draining process.
After you are satisfied with the draining, apply your new crush washer to the drain plug. Add a bit of oil to the threads, and hand screw the drain plug into the diff to ensure that you don’t cross thread. Screw it in until snug.
Then take your torque wrench, and torque the bolt to 36 ft lbs.
Now you are ready to add the new fluid. You’ll need a hand pump to make life easier. Just attach the base of the pump to the fluid bottle, and the hose to the fill plug of your diff, and start pumping. I had no trouble getting 3 qts into my diff, but you’ll want to watch for the fluid to start seeping out of the fill hole.
Once the fluid starts seeping out of the fill hole, stop pumping, and apply the fill plug with it’s new washer. Screw it down hand-tight. Get all of your stuff out of the way, and take the truck for a spin around the block. When you get back, remove the fill plug, and pump in more fluid until it starts seeping out again. I was able to add about .1 - .2 qt more.
Plug the fill hole, wipe away the excess fluid, and torque the bolt to 36 ft lbs. You’re done!
FRONT DIFF
Start by removing the lower skid plate. There are four 12 mm bolts that hold it in place. The front two bolts are set into the plate a few inches. I used a 3” extension to get them out.
Sorry about all the mud; still cleaning up from my muddy hill climb a few weeks ago. If you’ve been mudding in your truck, I advise you to pull the skid plate and clean up behind it. There was tons of mud behind the plate.
Looking from behind the front left wheel toward the front of the truck, here’s what you see. Two bolts are shown; the other 2 are a mirror image on the right side.
Pay attention to the tabs in the skid plate that rest on the frame to help support it. There are 2 up front, and one in the right rear. You'll want to make sure you put it back like this when you're all done.
Once the skid plate is out of the way, there’s a clear view of the front diff from behind the left front tire. It’s cramped in there, so you could consider jacking the truck up to create more space to loosen the bolts, but be sure to lower it back to the ground before removing the drain plug so that you get proper drainage.
Again, remove the fill plug first using a 10mm hex head socket. Mine required a couple taps to the socket wrench with a rubber mallet to break the bolts fee. Once the fill plug is out, remove the drain plug with the same 10mm hex head socket.
Set the bolts aside, and let the fluid drain out. This time I jacked up the right side of the truck to get as much old fluid out as possible.
Once the fluid has drained, apply the new copper washer to your drain plug, and hand screw the bolt into the diff housing until snug. Then use your torque wrench and tighten to 29 ft lbs.
Follow the same process for adding new fluid to the front diff. Use your hand pump, and pump in about 1.5 qts into the fill hole, or until fluid begins to seep out of the fill hole. Apply your new crush washer to the fill plug, and hand screw it until snug.
Get your stuff out of the way, and take it for a spin around the block, allowing the oil to warm a bit and settle. Once back in the garage, remove the fill bolt and pump in more fluid until it begins to seep out the fill hole (I got about .2 qts more in). Hand screw the fill plug back in until snug, wipe away the excess, and then torque it to 29 ft lbs.
Finish the job by replacing the lower skid plate. Be sure to align the notches on the front end of the plate so they rest on top of the cross member, and the notch on the rear right of the skid plate into the hole just to the left of the right rear bolt. Once you get these notches in place, the skid plate will rest in place so that you can screw the four bolts back in. I just wrenched them down hand tight.
TRANSFER CASE
Transfer case takes a little more than 1 quart of oil (approx. 1.1 qts). I used 25 ft lbs for the torque spec for both the drain and fill bolts.
Loosen and remove the fill plug first using a 24mm hex bolt socket. Some fluid may seep out of the fill bolt when you remove it – this is Ok.
Loosen and
slowly remove the drain plug next using the same 24mm socket. Be careful! Fluid may squirt out with some amount of pressure, so be ready with your catch pan. As the fluid drains, you’ll need to slide your catch pan closer to the transfer case as it begins to trickle out.
Give it a good 10-15 minutes to drain as much of the old fluid as possible. If you like, you can jack up the front end of the truck to help the draining process.
Once you are down to a slow drip, slide the new crush washer over the drain plug, and screw it back into the case. Apply 25 ft lbs of torque and tighten the bolt.
To apply the new fluid, follow the same process you used for the diffs. Apply the base of your hand pump to the new bottle of fluid, and the hose end into the fill plug of your transfer case. Start pumping, and add 1+ quarts of the new gear oil.
You’ll know it is full when gear oil begins to seep out of the fill plug hole. Once this happens, remove the pump hose from your transfer case, and screw the fill plug (with new crush washer) into the case until hand tight. Clean up the fluid drips on your case, and using the torque wrench, tighten the bolt to 25 ft lbs. (You can optionally screw the bolt hand tight, drive around for a few minutes and engage the transfer case, and then return and top off the fluid before torque’ing the fill bolt.).
That’s it! Start the truck, check for leaks, and check for leaks again in 24 hours.
Hopefully this detailed write up and pics will help someone trying this out for the first time.