How To: Differentials and Transfer Case Fluid Service

This is a step by step guide for how to change the fluids in your front and rear differentials as well as your transfer case. If youre comfortable changing your own oil, this is something you can tackle without any specialty tools.

Note: All oil quantities are found in the owners manual.
Front Differential-approx. 1.5 quarts
Transfer Case-approx. 1.5 quarts
Rear Differential-approx. 3.2 quarts

Tools:
24mm Socket-drain/fill plugs on rear differential and transfer case
12mm Socket-Front skid plates
10mm Hex-drain/fill plugs on front differential
Oil Drain Pan
Quart pump and hose



Parts:
Transfer Case Fill Gasket 90430-18008
Transfer Case Drain Gasket 90430-18008
Front Differential Fill Gasket

$14 12157-10010 Toyota Oil Drain Plug Crushable Steel Gaskets Set of 10 OEM 12157-10010

12157-10010
Front Differential Drain Gasket

$7 90430-24003 Front Differential Drain Plug Gasket

90430-24003
Rear Differential Fill Gasket 12157-10010
Rear Differential Drain Gasket 12157-10010

Oil:
7 Quarts* of 75w-90 gear lubricant is what I used. ranges in price from $5-$15 a quart.


*this will give you extra, I finished with 1.5 quarts leftover

Rear Differential
1.Locate the drain and fill plugs on the rear bell

2.Break the FILL PLUG loose FIRST. if you break the drain plug loose first, drain everything out and find out you can't get the fill off, you're in big trouble.
3.Take out the fill plug, then break loose and remove the drain plug, mine looked like this;

4. Let the oil drain out, 10-15 minutes for everything, mine still had a drip at this point but it was empty enough.
5. Put on the correct new washers before reinstalling, note that the one with the magnet is the drain plug

6. Attach the pump to the first quart

7. Start pumping! the manual states that both differentials and the transfer case are full when oil drips from the fill hole.

8. Once full, reinstalling and tighten the drain plugs. these don't need to be absurdly tight, hand tight will do, just make sure the washers compress, thats how they work.

Transfer Case
1. This process is largely the same as the rear differential, start by breaking loose the fill plug, its to the right of the drain plug, followed by the drain.

2. Let all the oil drain out, replace the washer and reinstall and tighten the drain plug.
3. Fill the transfer case the same way as the rear differential, until the oil drips from the fill hole.
4. Replace the washer on the fill plug, reinstall and tighten it.

Front Differential
1. The front differential is different only in the washer for the drain plug and the tools needed.
2. Remove the front skid plate and transmission skid plate. 12mm socket needed for this step

3. The front differential takes a 10mm hex key, be careful to not round off the plugs. A ratchet and hex key works much better than a conventional allen wrench

4. The drain and fill plugs are on the drivers side, drain is to the front of the vehicle, fill is towards the rear. (excuse the crappy pictures, its dark down there)

5. You guessed it, drain the oil out and replace the washer with the new copper one on the drain plug, reinstall and tighten.
6. Refill oil till it drips from the fill plug, then reinstall and tighten.
7. Reattach your skid plates, clean up, and go for a test drive!

Note: This is a good time to cycle through four wheel drive high and low, exercise the transfer case and front differential a little bit to cycle the oil and put some load on the parts.

 

@Bob i got a new one for you!

 

Good Info! I will be doing this in the Spring. Got 170K V6 SR5 Auto 4WD...good maintenance practice and easy!

 

thanks! i don't know why i didnt do it earlier, so easy. probably the smell lol

 

Hey new user. Nice post, can anyone help me find a replacement T Case fill plug? Mine is stripped real bad. This might be it but im not sure... https://parts.lakelandtoyota.com/p/...-CASE-LIMITED-PACKAGE/4169540/9034114012.html

Thoughts?

 

https://www.ebay.com/itm/NEW-Genuin...d=182327326200&_trksid=p2385738.c100677.m4598

https://parts.lakelandtoyota.com/p/...-CASE-LIMITED-PACKAGE/4169540/9034114012.html

Might be worth a call to the dealer just to double check though...

 

Another tip: have an oem replacement plug or two ready for the front diff. Had the same setup on my 2015 Tacoma and they were WAY over tightened from the factory. Had to go buy a large breaker bar to bust loose and almost stripped one.

 

Take it to a shop with a lift if you stripped the plug, then change to 24mm lexus plug, and don't over tighten.

The OP here looks like he has a rust issue creeping in. Time for maintenance?

Did my RD in driveway. Took 20 minutes. Two bolts. Simple. Three quarts of Valvoline W80 90 conventional.
I expect the FD fluid will be cleaner after 150,000 miles. Rear looked ok after 150,000 miles. Will remember to change RD again at 225,000 miles.

Why do posters panic over this unneeded maintenance - with no Toyota schedule. Overkill, like everything else?

No one needs to buy expensive synthetic for differentials. Dino is perfect for normal driving - especially if you are ever going to change it again.

Note: If you have 2WD there is no "front" plug to fill on a differential. 2WD don't have a front differential.

 

Thanks for the info @wnelax04sr5 make sure everyone torques the drain and fill plug properly;
Front,
Drain Plug - 10mm hex bit, 29 ft/lbs
Fill Plug - 10mm hex bit, 29 ft/lbs
Fill quantity - 1.5 qts.

Xfer,
Drain Plug - 24mm socket, 27 ft/lbs
Fill Plug - 24mm socket, 27 ft/lbs
Fill quantity - 1.5 qts.

Rear,
Drain Plug - 24mm socket, 36 ft/lbs
Fill Plug - 24mm socket, 36 ft/lbs
Fill quantity - 3+ qts. (6.3 pints)

Can't remember if this is V8 Specific or V6 Specific or both, Cheers!

 

That front drain plug torque spec seems a bit high. Mine only calls for 20fp’s?

 

Appreciate that I also confirmed from my Haynes guide. Hopefully, no one stripped a nut since the last post!

 

Gonna do this soon on my truck soon since I’m sure previous owner never did it. Replacing fluids with some good old AMSOIL

 

Great procedure. Thank you. I followed it for rear diff yesterday. Doing front and transfer this weekend. Super helpful!

 

Thanks. Good write up.

 

so i have the dreaded stripped drain plug. is the only fix to weld a 12mm hex to the plug? if so, might have to take it to a shop

 

Hi, what transfer case fluid did you use?

 

I also spoke to Toyota and they said they add a product called BG LSII limited slip additive to the diffs and transfer case, along with the 75w90 oil. Is this considered standard or necessary, from your experience?

 

Never heard of it unless they’re buying bulk fluid and adding that to bring it to spec (if you talked to dealer)

I just use Mobil 1 for diffs and royal purple synchromax for transfer.

 

Thanks, I was also surprised to know that they use the additive.

 

Is this the one you use? How many of these bottles do you use?

 

yeah. Takes less than 2

 

Do any/all of these apply to the 4.7L V8?
Unless I just missed it the OP doesn't specify but I assume these are for the 4.0 V6.

I just spent ~10 minutes on the phone with the only local dealer near me's parts dept and got nowhere. After giving my year and model and asking for a transfer case drain plug gasket all she kept coming up with was a transfer case output shaft seal 90311-41012. She kept asking me if it might be called something else. lol I gave up.

 

V8 here. these havent let me down yet... but YMMV

Differential and Transmission/Transfer Case Drain Plug Crush Washers Gaskets for Toyota 4runner Tacoma Tundra FJ Cruiser Land Cruiser, Replacement for The Part# 12157-10010 90430-24003 90430-18008..

https://www.amazon.com/Differential...refix=4runner+crush+washer+pack,aps,48&sr=8-2

 

Thanks for the reply. So it does appear the same Toyota gasket part numbers do apply to the V8. Thanks.

After having been burned too many times by aftermarket crap, even by what I used to feel were good brands like Moog and Napa's premium options, I tend to only consider Genuine Toyota or OEM (ex: Aisin, Denso, etc) replacement parts any more, even for something as simple as a fill/drain plug gasket.
Thanks for this thread.

 

$14 12157-10010 Toyota Oil Drain Plug Crushable Steel Gaskets Set of 10 OEM 12157-10010

12157-10010 TAKES QTY 3 TWO FOR REAR DIFFERENTIAL AND 1 FOR FRONT DIFFERENTIAL

$7 90430-24003 Front Differential Drain Plug Gasket

90430-24003 TAKES QTY 1 FOR FRONT DIFFERENTIAL
90430-A0003 TAKES QTY 2 TRANSFER CASE

sorry for the caps, this was a copy and paste. This is what I used for my V8. Cheers!

 

Thanks for the info, i need to fix my 4wd actuator & will change the fluid at the same time. Going with Valvoline Synpower 75w90.
Cheers!

 

Has anyone used a gasket maker like Permatex instead of the fiber gaskets?

 

It should be noted for noobs, the smell of this type of oil is possibly the worst thing you've ever smelled.

 

Wouldn't it be a lot easier and a lot less messy to just use the correct gaskets?

 

Yes, sorry, my question might have been misleading.
I was thinking about the actuator for my transfer case, I need to replace it and was wondering if I could just use gasket in a tube or if that's a fail...