Transfer case oil leak

do you have a part number for this seal?

 

@3JOH22A do you know the part number for this seal? I took a look and also couldn't find it.

 

when you remove this housing are there two seals behind the housing? mine is an AT I'm trying to figure out what seals to buy. I went down to Toyota dealer and it's confusing. not sure if there is 1 or two seals behind the extension housing and the parts guy seemed to think it's just 1 seal there.

 

On an automatic, I believe there is one seal hammered into the back of the transmission. If I remember right, the transfer case has a male spline with a splined female coupler tube that goes onto the t-case male stub. Then that coupler goes into back of the auto and the OD of the coupler seals to the seal in the abck of the transmission.

At the transfer case, the input shaft (male) sticks out and is sealed by the seal in the 4 bolt cover. There is only 1 seal in that transfer case area.


My previous comment mostly dove into the manual transmission details, where there is a true oil seal on the transfer case only and then an o-ring on the transfer case input housing, which seals the transfer case to the transmission. Which means assuming the o-ring doesn't spring a leak (unlikely), then any leakage of the oil seal in that setup would mean fluid goes from either transmission into the transfer case, or vice versa. But none of that is relevant to your situation. You should have the setup as I lined out a few lines up. Transmission to coupler seal, coupler, transfer input to transfer input cover seal.

From this diagram, I would say that if you are leaking transmission fluid, you need 35015J, whereas if you are leaking transfer case fluid, then you need 36102F or the whole front cover piece, 36102D.

 

I've been in contact with a TW member that did this leak job on the T case on a MT. He states when he pulled that extension cover housing 36102D off there is Two seals behind it. Maybe the AT is diff? just trying to make sure I source all the seals before I pull the T case and that extension housing off. the leak is Deff coming from the T case and not the Tranny.

 

I haven't been inside one of these transfer cases, so that guy may know more than me....but I can't possibly think of why there would be a second seal further in. There is a seal on the other side at the rear driveshaft, but that's all I'm aware of. As far as I know and also according to the diagram, I see the very front seal that is installed into the small bolted on housing, and then there is RTV silicone at the housing where it bolts on.

Maybe he is talking about the o-ring and the seal that the MTs have?

Aside from the bolted on cover and the spline style and count, I don't think the AT vs MT cases are any different.

 

Yea i'm not too sure. Here is a pic of his removed extension housing it looks like 1 seal. but I do see two seal grooves on the input shaft in this second picture of his maybe he replaced the seal on the transmission end too? i'll circle back with him

 

So...I was wrong. I have never seen this next diagram before... I narrowed it down by manual transmission this time and found a new diagram - there ARE 2 seals in the MT input housing on the transfer case. The AT has 1 seal.

My guess is that Toyota doubled up the seals to prevent the t-case and transmission from leaking into each other, in case one goes bad. So basically, transmission oil is splashing up against the 1st seal, and transfer case fluid is held in place behind the rear seal.

Regardless, you just need the one transfer case seal for an AT, plus you need to seal the seal housing with RTV.

 

Looks like part number for 36102F Seal would be 90316-37001? i'm thinking does this seem right? one site shows that, but says not compatible with my truck lol. I think i'll just go back down to Toyota dealer and order the one seal through them glad I know it looks to be just 1 seal on the AT and where the confusion was. Thank you. Those above diagrams are for the third gen correct?

 

Yeah, they're for 3rd gen. It is a bit difficult to find the right part through these diagrams.

I am having trouble confirming the part, but I am thinking the best likely chance of success is 90311-43008. I think the one you posted might be for a transaxle on a Highlander, but it's hard to tell. The 90311-43008 part number seems to have been on all 4Runners, Tacomas, FJs, as well as some Tundras and Sequoias. I have a feeling that is what is needed, but it would be best to confirm.

 

Yep it is two seals for MT and one for AT found this in the FSM as well shows the two vs the 1 for AT ty for the help BLtheP

 

Posting this info incase anyone else stumbles upon this and needs help.