UPDATE: Fixed it, procedure in post #14 for anyone contemplating doing this and want some directions

I assumed output shaft seal(s), but after cleaning it up, topping the oil off, and running it for a few weeks I don't see any signs of leakage right under the output shaft. The oil is just everywhere. And appears to be coming from the top of the transfer case. I assume the only thing up there that would leak is where the shifter connects?

I've checked the transmission fluid and don't see any evidence that the oil is leaking into the tranny.

So anyway, is there any possibility of getting to this seal without yanking the T-case out? And if the answer is no how rough is that as a DIY thing? I enjoy doing my own wrenching, but unfortunately don't have a lift.

If I end up having to have a shop do it, what kind of price range should I expect?

Thanks for any info.

Post pics please

Here ya go, as good as I could get with my cell phone.

Oil is basically everywhere, but there isn't any pooling right underneath the output shafts. Shining a light up the side I can see oil up at the top of the T-case as well, way too high for it to be coming from a leak near the bottom.

I have filled the T-case back up a few times now, it seems to take a couple weeks of daily driving before it's noticeably low. It looked this way when I bought it earlier in the year, so who knows how long it was driven while low on oil. I'm thinking if the leak was anywhere but at the very top it would have drained itself of oil and destroyed the T-case.

This is a 2002, BTW.

Did you overfill the oil? Did you let the oil to drain from the fill port?

I just pumped some in until it started coming out the fill port. Let it sit for a few minutes, then put the bolt back in.

It leaks a bit every day. Not a lot, but enough to see on the pavement where I park.

If it's leaking from the top then I would say it's leaking from the tcase shifter oil deflector, you might want to check the tcase breather also, make sure it's not plug

Check the condition of the breather stat.

I believe that's the case, yes. Is there a way to get to that and fix it from the top? Like taking apart the center console, shifter cover, etc...?

From what I read on that there is no breather on the T-case. There's a closed loop up top between the transmission and T-case to equalize pressure, but no open vent like the front and rear diffs. Is that not true?

Yes, remove center console, disconnect shifter form trans., a few bolts/nuts and you should have access to the tcase shifter assembly, it's pretty simple, remeber there is two gasket one from tcase mouting surface to oil deflector and one from oil deflector to tcase shifter base


When you gain access to the tcase shifter look towards the top left cut out on the floor at the trans/tcase there should be a breather

I am also having this same issue with my 02 runner we have. The 96 we have has never had this issue and it has over 270K. Ive replaced the front output shaft seal along with their 75-90 super that is suppose to not "foam" as much and thats when i realized after the clean up and putting a few miles on it that it is coming from the top as well. Saw a post some where that the seal up top for the shifter had loose bolts on one guys 4runner. Just have not had time to rip the interior apart on it.

Thanks for the info.

I removed the shifter assembly today and confirmed that my leak is coming from there. Crazy thing is one of the bolts that holds the 4WD shifter onto the T-case is missing. I guess that might be a problem, lol. In any case there is oil all around it so that's the source of my issue. The gaskets may be fine, but I'm going to get new ones anyway, might as well if I have it apart.

I could not get the shifter assembly completely off though, could only pick it up a few inches. The transmission shifter is connected straight through, no way I can see to disconnect it up top. There's a metal piece that goes down towards the drivers side, and apparently is connected to the transmission below. It would move a bit, but not much. So I guess I have to get underneath and disconnect something from the bottom? Not sure, didn't look into that today. If I'm wrong and there's a way to get it free from up top I'm all ears, that would be nice. I need to completely remove the shifter assembly so I can get to the T-case below.

This is a 2002 with the push button 4WD, if that makes a difference.

I had gear oil leaking from top of my tcase. It was a bad shifter gasket. Got a new one from dealer $5. No more leaks. Most common reason why its leaking from top. Did this actually few days ago.

I'll second this. I thought I had a major leak as well, but ended up that the breather was the problem. No issues since fixing that.

Posting this for anyone searching for this issue in the future. Mine is an '02, so if you've got an '01 or '02 auto everything will be the same. Probably very similar for earlier years, but I'm sure there are some differences.

Bottom line I had a leak from up top where the 4WD shifter connects to the T-case. Getting to it is fairly straight forward. Remove the center console and trim around the transmission shifter. There are two bolts down inside the compartment in the center console, and two screws up near the shifters that screw in from the sides. The rest of the trim pieces are just held in place with clips that let loose pretty easy.

There's a small screw on the side of the 4WD shifter, remove that and you can pull the knob off. The leather boot is attached to the trim piece, once you pull both off you can get to the underside of the trim and pop out the boot. The 4WD knob has a wire running to it which you can disconnect if you like, I didn't. I let it hang there in the driver's side footwell. It doesn't get in the way.

Once you've got that out of the way you can see the plate that both shifters are connected to. At the bottom left some of the wiring is clipped to that plate, you have to pop that free. Now there's 8 bolts around the plate the shifters are on. Remove those. The ones at the front will require a flex adapter to get to them, and you may need to turn the ignition on and shift into drive to get the shifter mechanism out of the way. Just remember to put it back in park after you get those bolts out, you'll be disabling the shifter shortly. You'll need a pretty long extension as well to keep the wrench clear of the shifters. I used a 12 inch. Up at the front there's a white wiring connector you need to disconnect. It's pretty obvious.

Now climb underneath and disconnect the transmission shifter arm from the tranny. It's a single nut, mine came loose with a little PB Blaster. You get to it from the driver's side, pretty much directly below where you're working up top. Sorry, don't have pics, was in a hurry when I did this, but it's not hard to find. The arm comes down from above and bolts onto a rod that goes straight forward alongside the transmission.

Now with a little bit of twisting and pulling you can get the entire shifter assembly off. There's a second rubber boot on the 4WD shifter connected to the plate, you need to work it up and off the shifter as you're pulling the assembly out. And that arm you disconnected below doesn't come out straight, you have to angle the whole assembly towards the passenger side to get it through the cutout.

Now you can see where the 4WD shifter connects to the T-case. If your leak is coming from here you should see a bunch of oil all around it. If it's dry and clean, close it back up, no need to go further. I was missing one of the bolts, and people have reported these bolts are very loose sometimes. So if that's the case you might try replacing any missing bolts and tightening them all down good. That might do the trick. I figured I might as well replace the gaskets as well.

Looking down at the T-case on the right side where the shifter bolts onto it there's a breather tube. It's a straight rubber hose that connects just a few inches up to the transmission. Across the other side of the transmission is the actual breather valve. There is no breather on the T-case itself, the tube simply equalizes pressure between the T-case and transmission, and the valve on the transmission acts as a breather for both. Be careful of the tube as you remove the shifter, it's connected to the piece you're taking out. Mine I discovered was in two pieces. Almost looked like it had been cut in the middle, so I had to replace that.

Once you take the shifter off there is another very thin metal plate underneath. That's the oil deflector, and it is listed as a non-reusable part. You can reuse it, but be VERY careful removing it. It's super thin and you can easily bend it all up trying to get it off. Use the blade out of a box cutter to pop it loose and you should be ok. It's not expensive, like $17 from the dealer, so just replace it if you like.

Make sure you buy TWO gaskets. The parts guy at the dealership tried to convince me I only needed one, but I had read many discussions that said there were two. So I bought two, and I needed both of them. There is a gasket on both sides of the oil deflector, it's easy to miss unless you're thorough. They're just the flimsy little paper gaskets, and the remnants of the old ones can be easy to miss unless you clean up all the surfaces very well (which you should). Cleaning up the old oil deflector is a pain the @ss, so yeah, just buy a new one.

I used gasket sealer on the bottom gasket, the one between the oil deflector and the T-case. Didn't bother on the upper gasket. That's the way it was from the factory, I had rubbery gunk around that bottom seal, the top one just peeled right off. This is a tiny seal, so go real easy on the sealer. You don't want that stuff squirting into the T-case when you bolt it down.

Put it all back together, then change out the oil in the T-case. It's 75-90, GL-4 / GL-5 rated. Do yourself a huge favor and remove the fill plug first. If it is rusted on real good and you have to go buy a breaker bar or something to get the job done that's much easier BEFORE you drain the oil.

Sorry for dragging this extremely old thread back to life, but I am having this same issue on my 2000 SR5 with the manual style T-case shifter. I only have the single metal gasket between my shifter and T-case and I cannot for the life of me find the other gaskets online, can anybody help?