Why the transfer case leaks on my 2016 Tacoma

I bought this truck used, it is eight years old 72,000 miles on it, the previous owner said there were no issues with it. It turns out he had been wiping the oil off the transfer case for years and didn’t tell me.
I took it apart today to find out that this is how much silicone Toyota used on the little cover plate that goes over the input shaft on the case.
The bolt holes into the transfer case are through holes so oil will leak past the bolts and out the bolt holes and it probably isn’t a problem if Toyota had put some silicone around the bolt holes on the cover.
I think the newer years must have a gasket in place so I will go to Toyota in Canada here on Monday and probably pay $50 for a paper gasket that should’ve been on there from the day it was made.

Another thing was the green locking compound they used was gummy.
I need to find out what colour Loctite I should be using to reinstall these things because I can’t clean the threads due to the fact they’re thru holes. I can’t be spraying brake clean into the holes.

 

No gasket

 

I have the same year in Offroad trim.
40k miles and haven't noticed anything.
Certainly something to watch for.
Thanks for sharing.

 

Looking into this further, I saw another cover that has the same skimmed amount of sealant. It seems odd to put sealant on and then not put enough to do the job.
Hopefully it is just the seals and the $15cdn Toyota O-ring (unless I can match it with a $2 nitrile oring from an auto parts store) that are actually leaking. Although the screw holes go right through into the cavity of the transfer case I’m hoping it isn’t the bolt holes that are leaking because there is nothing to seal them other than green Loctite.

Last resort if new seals don’t work might be to have to machine the cover and put orings at each bolt.

 

You can seal bolt holes with silicone, toyota does it on the 8mm water pump bolts. Sealing this cover isn't rocket science and it sounds to me like you're overthinking this. I'd skip locktight on those bolts, it's not needed. Just clean the thing off, replace the oring, seal the bolt holes and put a coat of ultra grey permatex on the sealing surface.

 

Exactly.

 

That’s a little overkill. You just got a poor sealant job. There are thousands of trucks that don’t have this leak. None have a machined cover, none have an o-ring it’s just sealant

if you really wanna go nuts, you can get some Permatec & silk thread from Lycoming

 

I’m not over thinking it, I just don't want to have to take the transfer case out again

The bolts come with green loctite but it’s gelled like the fluid affected the loctite which I’ve never seen before.

I’ll clean them up and use Ultra Black RTV which I already have here and had planned to use on the cover unless someone can think of a reason why ultra black wouldn’t suffice.

Thanks for the responses.

 

ultra black should work fine

 

I believe that green loc-tite is for wicking.

 

I don’t have the seals out yet but it looks like the first one sits about 2mm out from the bottom of the bearing seat, I wonder if it’s supposed to go right down to the bottom of the bearing seat.
I can’t find any information on that.

I’ve also noticed both seals have worn grooves into the input shaft.

 

I bought SKF seals, one of them, SKF 17300 that auto parts store list using the Toyota number is too small, SKF has the wrong seal listed.
They have 2 seals side by side yet list different part numbers, one SKF works.
Does anyone know the correct seal?

 

Go to the dealer

 

My 2016 had a recall on the leaking transfer case.

 

I checked for recalls before I bought this truck and there weren’t any except for the upper mount brake light, at least hear in Canada there weren’t any recalls.

I will be talking to the dealer to buy seals today and will find out what their experience has been with this truck.
Since they told me there were no recalls and I have it apart now I doubt they’re going to help me with the repairs if there was one but I will give it a shot.

Thanks for that information

 

Silicone is such great stuff for so many things! I’ve seen Toyota do this as well.

 

Thank you.
I was going to use ultra black as I need to also seal up the bolts.

Seal packing looks looks like a premade material? Toyota used such a thin amount of sealant it was see through or non existent in spots.

Here also is wear on the shaft after 72,000 miles front the existing factory seals.

 

Most parts stores sell Permatex thread sealer w/lock.

As for the seal packing, I'd feel fine using black or grey.
Grey is suited more for trans and gear oil. But I've never had issues using black either.
Both colors say good for trans pans and differential covers.

 

The 1344 crosses over to Loctite blue 242
Which is interesting because what was sparsely on the bolts was green and it was gummy like it had never dried.
It was as if this transfer case is built when they were running low on supplies so they just got really skimpy on everything


Also today while installing the first seal, there are two holes between the seals which I’m not sure why they are there but they tore the rubber on the seal going in, and then I looked at the seal that came out and sure enough it was also torn because these little holes had burrs on them.

luckily, I work in a machine shop and have the tools to clean up the holes and clean up all the services, but it just doesn’t make any sense what the holes are for, why there were still burrs on them and why there are two seals side-by-side that are different although they are the exact same size.