NikoKourm

I've been having a problem ever since I noticed it originally that there is a leak between the transmission and transfer case right where the gasket sits. This has been the only spot that it has been leaking from in all instances.

Here's the story for my 2004 Chevy Silverado 1500 LS 5.3L V8:

I noticed that it was leaking over this past summer and I thought that it was due to that common issue with GM transmissions where a hole forms in transfer case. I thought this had occurred at the top of the transfer case, so I brought it to a shop and got their opinion. They told me that there was hole for sure at the top of the case and that the annoying whiny noise during high speed accelerations was due to the transfer case being empty.

So I took the transfer case off and inspected it myself. The old gasket was definitely bad and that might've been part of the problem. The guy at the shop was trying to get some money out of me (he did since they held it for the day). There was no hole, so I was still stumped about the leak. I still opened up the transfer case and installed the Merchant Automotive Upgrade Kit and resealed everything as needed. I put the new gasket in between the transfer case and transmission and went on my merry way... until the next day, when it started leaking again.

So time had passed, the truck went to my brother as I was at school. The leak got worse over a few months until finally one day the reverse and the whole transmission went. He never bothered figuring out what type of fluid was all over the front driveway and never took my advice of checking the transmission fluid, but anyways. I do the rebuild (unsuccessfully, of course - still working on it) and while doing the rebuild I noticed that the rear piston was cracked on the side. I figured this was my problem, I get a new one, new seal and new everything.

I put in a nice fancy gasket and went on my merry way. Although the truck wasn't driving properly, the leak was gone for a week or so. I come back home today so I can continue my trek in diagnosing what could be my problem with the transmission (I guess I will have to take everything off again) and I noticed that there was a leak again.

I tightened the gasket to the specs that the instructions called for on the back of the box. I'm wondering what could still be causing this leak to occur? I've gone through three gaskets since I noticed it back in the summer and none of them have worked.

As I go back and rebuild again, should I look into anything inside the transmission? Everything towards the rear seemed fine, the extension housing looks okay. Is it the extension housing or could the transmission shell be bad towards the rear?

Is it possible that since the input drum isn't sealing properly, that there would be an "overflow" of fluid to the back of the transmission to the point that the gasket can't handle it anymore? I doubt this is the case since the transmission should always be holding 12 quarts of fluid at all times (and since my transmission didn't burn out until the fluid level was way past dangerously low).

Also, should I look into some sort of gasket maker instead of using a gasket? I don't like this leak and it's been bugging me for some time now. Any suggestions to my problem would be much appreciated.

NikoKourm

Does anyone have any suggestions? I hate to bump the thread but I just pulled my transmission out again so I want to resolve this issue before it goes back on if and when it does.

I was looking at some other places, some people have said they placed a seal in the rear side of the transmission. I checked the remaining seals in my kit and none seemed to fit, at least on the outside. Could it be the bushing?

mrvedit

Are you sure its leaking between the trans and transfer case?
Since you have already replaced that gasket several times, either the gasket surface has a major flaw or the leak is coming from somewhere else.

Have the transfer case output shaft seals been replaced?

Nothing related to the input drum, sun shell or other parts is going to cause a leak.

NikoKourm

I did some reading up on it, it's either the bushing at the very rear of the case that is badly worn out or the seal at front of the transfer case. I am leaning towards the bushing since I think I replaced the seal on the transfer case, but I don't know for sure.

I am going to replace both since those are the only two things that could be causing the leak.

NikoKourm

Also, there shouldn't be an excess of fluid in that connection to the point that the gasket can't hold it anymore is what I understand. In this case, it has been enough fluid to drain out the transmission gradually.