15 tundra differential fluid change and drain plug gaskets

Well...I know that’s a deep subject, so don’t give me a hard time please...yesterday I was doing a little research on the interweb and realized I may need to look into maintenancing the oil in my rear differential, transfer case, and front differential. I now have over 37,000 miles on my truck. I did find a few threads on other forums about this, but most covered older models. A search on this forum turned up nothing, so thought I would jump into it here (please forgive me if I am duplicating one).

I figured the dealership.....won’t mention names(Steve Landers in Little Rock) would know what drain plug gaskets I would need for all three, so made a short detour on the way home to pick them up. I approached the first guy at the parts counter, as the other was on the phone. He was super nice and asked if he could help me and I said yes. I explained my plans to change the fluids in all three housings, blah,blah,blah and need the drain plug gaskets for replacement. This is where it got interesting...His response to me immediately drew a red flag... He said “do you know which ones and what size”. I said “no, but there is a fill plug and drain plug for each one, so I would need at minimum six”. He said “oh, I know what you need” and pranced off into the parts room. He came back with six crush washers that look like this:

I asked him he was sure these are correct and he said “yes”. Granted now, I was thinking these guys do this maintenance a hell of a lot more than I have, so he surely must be knowledgeable. I asked him if he understood what I needed and he reassured me these are what I needed. He never used the computer to look anything up...Red Flag again. I said ok, how much do I owe you and he said lnothing, thery are on the House”...Red flag again. I didn’t want to argue, so I said thank you and left. After I got home, I did a little more research on the interweb and I believe he may have given me too much of one thing. If I am not incorrect, I only need three of these crush washers, a copper washer, and two aluminum flat crush washers. Any one out there done this and you can confirm?

The next question is no one has 75W/85 gear oil in stock, only 75W/90. Not much different, but thought I would be sure by calling the dealership and getting some detail on that. After playing pass the phone with receptionist and parts department twice, along with service rep, they finely got to a repair man in the back. After explaining the issue I was having, he said the 75W/90 would work fine as they use 80w/90weight at the shop there and will need two quarts each, a total six quarts... I know he wrong there, cause I checked the manual. Interesting...Anyone out there have any insight or comment on this? I plan to use mobile one 75W/90 and will need 8 quarts. The front diff takes 2.2, transfer, 1.6, and rear diff 3.8.

I plan to try and do this maintenance tomorrow. Could take pics if requested...

 

for the washers you will need:
12157-10010 - rear diff drain/fill and front diff fill (what you have)
90430-18008 - t-case drain/fill
90430-24003 - front diff drain

 

Thanks for confirming that for me. I will be headed back to the dealership tomorrow.

 

3 changes on diffs on Tacoma and never changed washers. Never had a leak. Changed the transfer case at 50k and fluid looked new. As few miles as most people use 4x4 I don't see need to change the transfer case fluid.

 

Good to know that and thank you for the info. Call me OCD......I love my tundra and plan to keep it a long time. I don’t mind paying that little extra for a little maintenance, but don’t trust the dealership, as mentioned above. It is good to know though that these plug gaskets can be used multiple times. What weight gear oil did you use?

 

FWIW, if you decide to do the transfer case you might want to check with your dealer to verify the correct fluid. In 2014 Toyota changed the fluid to a straight 75W which is quite a bit lighter in weight than 75W-90 and also supposedly has significantly different friction additives. I looked and couldn't find it but there is a post here somewhere on this. As far as i know 75W-90 is still applicable for the diffs.

 

I did see that in the maintenance manual. Glad you mentioned it. It makes me wonder why the dealership said they use 90 weight gear oil in all three. I almost feel on my own we I try to get information from them. This dealership service department is horrible. I guess i am gonna dig a little deaper into that. Hell, I don’t know of anywhere you can even find 75 weight in a store. When i asked, the dealership parts department said they don’t even carry it in stock. WTF?

 

I remember reading that 75W was, at the time, only available thru the dealer and had to do with Toyota switching from a Japanese transfer case to Borg Warner. Might be a good question for Tim @trdlife , he's a Toyota master tech.

 

Guys, I crawled under my truck and noticed the rear differential has a large amount of residue around the main seal.
This truck has 37,800 miles on it. Is this normal?

Please ignore the splatter, i greased my driveshaft last week and a excess around the u-joints slung off going down the road.

 

Well, for the 2015, some of the washer/gaskets you listed are not needed. I only needed three of the zinc crush washers and one copper washer. The rear diff takes two crush washers, fill/drain and the front diff takes one crush washer for the fill and one copper for the drain. The transfer case has two, drain/fill, set screw bolts that are self sealing and don’t take washer/gaskets. Not sure is this is just year 15-current, but certainly different than other forums have indicated. See pics below.

No washers on transfer


Here a shot of the front and rear diff.


Crush washer on top (fill) and copper on bottom (drain) For front diff.



Crush washer of rear diff (drain).
Crush washer on rear diff (fill).

This my be helpful to someone with a gen 3 year 15 or newer. I used a total of 7 1/2 quarts of mobile 1 synthetic 75W/90 gear oil as recommended from a local dealership (not Steve Landers Toyota).

 

75w-90

 

sorry for the late reply but yea that is the correct new weight, as far as why not sure they wont tell us everything but i suspect its from the new transfer case. Now thats is the recc fluid type now there are other weights that are acceptable but the only recc the one they want to put in. we get a special synthetic bulk blend from castrol that works in all toyota. and this is i think what most shops, dealer and aftermarket use now a days.

 

@trdlife thanks for confirming that. I appreciate a Master Technician weighing in on this. I may be reaching out to you in the future if the need demands.

 

not a problem anytime.

 

getting ready to change both diffs and transfer case on my 2016 came across this post. just to verify I can use 75w90 in all 3?

 

Yea that’s what I use in mine

 

what brand do you use? I was looking at mobil 1

 

I opted to not use 75W90. In Truth, I initially changed my fluid for the first time with 75w90, drove it for about 150 miles and then swapped it back to the factory recommended Toyota transfer case oil. I feel alot more at ease knowing I used what it called for. I recommend using what it calls for and not going with 75w90.

 

I used 75w90 Royal purple in front and rear diff as well as the transfer case. That is what I found was what I thought was supposed to be used in all three but it was for the second Gen. I also found a did not need any crush washers for the transfer case. I did not change the transfer case fluid back to Toyota 75w. So far everything has worked fine I exercise it once a month. I do notice it will not stop flashing 4hi when I’ve disengaged it until I make a slight turn. Other than that it works fine. I do want to change it though.

 

On Diffs, I would go with mobile1, but transfer case is a whole different story. To be safe, I would stay with the Toyota 75W transfer case oil. I actually called the manufacturer and they said not to use 75W90. I was told it will cause issues with the actuator that engages the 4x4 over time. Something to consider.

 

Yeah dammit. I probably don’t need to touch the front and rear Diff’sas they were done about 15 to 17,000 miles ago. I have to check my records. So at least I won’t be spending money on all three to swap this out.

So you don’t think the royal purple was good enough for the front and rear diff? Mobile1 better?

 

Check this video out...https://youtu.be/uQ_vxdO_9nc

It represents motor oil at cold temps, but interesting nonetheless.

 

We have bulk Castrol at my dealership it’s what I use, Mobil is great too

 

I use full synthetic German Ravenol.
http://www.ravenol.de/en/oil-guide.html

*HINT: On the oil guide you must select "car" to get you to select the Tundra model.

75W for transfer case
75W-85 for front and rear differentials.

I got mine from Amazon.

I gained .7 MPG by switching to this type. Just an added plus.

 

I have this project coming up this will be a big help.

 

For comparison of all oils Google " everything you wanted to know about oil but been afraid to ask " i raced stock cars for 25 years. When i first started racing i went through engines every year. After 3 years i found this site and changed oil brands . Engine life changed for the good.

 

im late to the party but wow dude nice find
my understanding about difficulty using correct weight Toyota fluids was the dealer only sold it in bulk (at least mine), so you cant just walk in and buy a few quarts. I agree with the other members regarding using the correct weight, putting something in there that does not match what the book says triggers my OCD. thank you for sharing this.

 

I'm getting ready to do my differentials (4WD, so front and rear) and am using Red Line 75W90. Will then figure out the transfer case.

 

Thanks for that McGov, Redline 75-85
https://www.redlineoil.com/75w85-gl-5-gear-oil

 

Would this work better than the OEM fluids and will this mess with the powertrain warranty? I personally think that the Germans make the some of the best when it comes to fluids or car parts. How many bottles did you buy of each fluid?