2nd gen 6MT transfer case to transmission

Everyone,

I have searched high and low for the answer to this question unsuccessfully. Here’s what I have going on.

I have a 2015 access cab 6spd 4WD Tacoma. I’m leaking gear oil from where the transfer case and transmission mate. A long time ago I did a FJ swap and not long after the leak started. I’m finally annoyed enough with it to address it.

I’m thinking it’s gear oil from my transmission cause when I (frequently) check to make sure the transmission and t case are full, I usually have to add a little to the transmission. That’s all I have to go on for now.

my question: is there a seal on thetransmission where the t case splines go into? Or is it sealed with the O ring only, on the housing of the T case? The onlytransmission output shaft seals I can find and threads to match are related to 2nd gen automatics and 1st gen manuals.


This pic is from another thread on here, it’s not my truck, however the parts are the same as mine. On the transmission where the t case splines go into, is there a seal in there? I cannot for the life of me find it, what it’s called or a part number. OR, is it just sealed by the O ring only on the t case?

I appreciate any advice

 

@Levy49 has some good (read bad) experiences with transfer case leaks in this area will probably be able to offer assistance

 

Pretty sure that's actually my thread you found, but to answer your question there is a seal that rides on the tcase input shaft to keep the fluid seperate from the trans, but the o-ring is the only thing keeping the trans fluid from escaping to the outside world. What I ended up doing was replacing both the nose cone on the tcase and the bracket where it slides into on the rear of the trans, I didn't notice anything wrong with the ones I replaced but it hasn't leaked since. I'll put the part numbers down below

O-ring 9672135063
Nose cone 3610235080
Trans bracket 3312135110

 

How difficult is the trans bracket?

 

Am I gonna need any gasket maker?

 

You will need gasket maker, a gear oil rtv I believe I used permatex but choose your favorite flavor, it's not difficult at all, it's only held in with 4 bolts, use a pry bar of choice to pop it off, clean up the mating surfaces of the old rtv then reinstall

 

Hell yea, thank you

 

Does the nose cone assembly come with the seals in it already?

 

yes it does come with the seal, that part number I gave you is highlighted in this diagram, and similar replacement unbolt it, remove old rtv, reinstall, there are some sleeves that live on the input shaft that the nose cone goes over, install it by hand if you have to install it by drawing the bolts down you will break them, if you end up breaking them its the part in this diagram that is 36216a (complete part # 3620171010)

 

Wow. Thank you so much! I’ve ordered everything and currently waiting on parts.

 

Today’s the day. I suck with taking pictures but I took the t case out and replaced the nose cone, all new gear oil grade gasket maker where it was called for. New O rings. That trans bracket looked flawless.

it’s all back together and I’m letting all the gasket cure for the day before I even start the truck. I’ll report back the findings.

there was quite a bit of gear oil in the void space between the trans and t case. Hopefully the problem is solved. I’ll keep the thread updated

 

Yeah mine looked mint as well but once I swapped it all out that fixed it. I hope it works out for you!

If not what I'd do is drill a small hole on the transmission side so you can get a bore scope in there to see where exactly it's coming from. That's what I ended up doing before swapping out all those parts

 

Damn. I opted on not messing with the trans bracket. Hoping i didn’t screw myself. It looked mint and I didn’t want to mess anything up. The cone on the t case looked like the input shaft seal wasn’t flush and the edge looked a little torn. The O ring on the outside looked fine though.

nothing leaked overnight. dry as a bone. Hopefully it stays that way after driving some

 

For me the leak never showed it's ugly head until I did a long drive, typically a few hundred km

 

Damn. Here I was feeling pretty optimistic about everything haha.

 

So far 3 days and 50 miles later, so good.

it’s still kinda early but prognosis is looking good.

 

Tomorrow will be a week with regular daily driving and so far so good. If anyone stumbles upon this thread in the future with the same problem. It’s fixed now.

new t case nose cone with o ring and the seals in the nose cone come installed from the factory. I put some grease around the exterior o ring. I used gear oil specific gasket maker.

I opted out of the messing with the trans bracket. It looked mint. Got lucky (I guess) that it was ultimately fine.

levy49 was a big help with the part numbers and previous experience. Thanks everyone !