1G Best way to temporarily seal leaking transmission case?

[XC92]

I rebuilt the manual trans on my '92 Talon TSi AWD a couple of years ago and although it's been working just fine as a trans it does have a very slight leak, likely between the mating surfaces of the 4 case sections because I probably didn't use the right RTV (Ultra Gray, probably should have used Black which is more oil resistant) and/or didn't apply and cure it properly (apply, mate, finget-tighten bolts, torque down after an hour, wait 24 hours to refill with oil).

I drained the oil and took off the end part of the case, the one furthest to the right or passenger side, with the trans still on the car, yesterday, cleaned off the mating surfaces and then applied Ultra Black and cured it the right way. But I suspect that the leak is also coming from the other mating surface interfaces, so I'm probably going to have to drop the trans and take it apart to seal all the interfaces properly.

But it's getting to be just too cold here to do that as I work on the car outside, not having a garage or indoor work area. So I'm going to have to put it off till the spring. In the meantime I do need to drive the car. So, I'm wondering if there's anything I can apply to the other 2 case interfaces to temporarily seal them to the extent possible until then, something like RTV, weatherstrip adhesive, Gorilla tape, Flex-Seal, etc. I won't be taking any extended road trips, just local drives of 10-30 miles every few days, in cold weather.

 

[Mech Addict]

If I were in your situation I might try wiping it down with denatured alcohol really well, and the apply some 2” strips of bituthene over the existing beads. I don’t know whether the case would get hot enough to make it release, but it should be flexible enough to handle the expansion that happens with aluminum.

 

[XC92]

If I were in your situation I might try wiping it down with denatured alcohol really well, and the apply some 2” strips of bituthene over the existing beads. I don’t know whether the case would get hot enough to make it release, but it should be flexible enough to handle the expansion that happens with aluminum.

Thanks. Never heard of it. Is there a decent substitute that's more consumer-based? I'm only talking a few months and not that much driving, and it's been leaking very slightly for two years now with maybe a loss of a few teaspoons of oil every month or so. I guess the key attributes would be oil and heat resistance.

 

[Mech Addict]

They sell this stuff at home depot. It’s mostly used as a waterproof membrane on buildings. I’ve seen it sold in 3’-wide rolls down to 6” rolls. I think eventually oil would make it “un-stick” itself from the case, but might slow it down for a while, especially with a slow leak.

 

[dwb]

I wouldn't discount Ultra Gray specifically. I've had good results with it on my trans as long as the surfaces were prepped and the tube was fresh. I didn't even let it set up before torqueing, but no oil until it cured. I did have a tube that must have froze or just got old. It didn't cure right and I had to redo that seal (oil pan).

If you can deal with the mess, and have plans to permanently fix it in the future, just keep an eye on the fluid level until then.

 

[turbomister2]

by no means am I serious but based on the commercial why not try flex seal or flex paste?

 

[XC92]

by no means am I serious but based on the commercial why not try flex seal or flex paste?

Don't have any actually but who knows, it might just work for a few months.

I wouldn't discount Ultra Gray specifically. I've had good results with it on my trans as long as the surfaces were prepped and the tube was fresh. I didn't even let it set up before torqueing, but no oil until it cured. I did have a tube that must have froze or just got old. It didn't cure right and I had to redo that seal (oil pan).

If you can deal with the mess, and have plans to permanently fix it in the future, just keep an eye on the fluid level until then.

I think I just rushed the sealing in my haste to get the job done, but since Black is supposed to be better with oil, I'll probably use it when I redo this in the spring.

They sell this stuff at home depot. It’s mostly used as a waterproof membrane on buildings. I’ve seen it sold in 3’-wide rolls down to 6” rolls. I think eventually oil would make it “un-stick” itself from the case, but might slow it down for a while, especially with a slow leak.

I'll take a look next time I'm in HD.

Btw, totally unrelated, but I was just there to buy an aluminum racing floor jack, in case anyone needs a new one. 3 ton capacity, 18.5" max height, low clearance, 58lbs which is on the heavy side but still manageable for anyone able to do serious auto work, usually $200 but now on sale for $160. I applied for their credit card to get an additional $25 off so $145 total after tax ain't too bad. My old trolley jack got the job done but just didn't have enough height so it required wood blocks which is dangerous, and took way too many pumps to get the car up.

 

[BLACK'98DSM]

by no means am I serious but based on the commercial why not try flex seal or flex paste?

"Hey guys, Phil Swift here. And I just sawed this DSM in half!"...

In my opinion, just let it leak and keep the fluid topped off. Anything you add to the transmission will need to be cleaned up later, and it doesn't sound like it leaks enough to make a 30 mile trip dangerous. Do it right when you can, don't make a mess now.

 

[turbomister2]

"Hey guys, Phil Swift here. And I just sawed this DSM in half!"...

In my opinion, just let it leak and keep the fluid topped off. Anything you add to the transmission will need to be cleaned up later, and it doesn't sound like it leaks enough to make a 30 mile trip dangerous. Do it right when you can, don't make a mess now.

I mean the man cut the floor out of a boat and sealed it , no way it can’t work

 

[DSMPT]

Before taking some action with RTV, I would make sure if the breather cap is not clogged up or the breather hole is not blocked off accidentally. When it's completely clogged up/blocked off, the transmission/t-case fluid leak/seep out through the locations that has weaker sealing due to building some pressure inside. Like seep out from bolt holes and the fluid go down by the case mating surface line. And that makes it looked like leaking from the mating surface. This is what happened to me before. I was almost going to disassemble the transmission to reseal but I didn't need to. I cleaned the breather cap that was clogged up, and then the leak completely stopped.

 

[XC92]

Before taking some action with RTV, I would make sure if the breather cap is not clogged up or the breather hole is not blocked off accidentally. When it's completely clogged up/blocked off, the transmission/t-case fluid leak/seep out through the locations that has weaker sealing due to building some pressure inside. Like seep out from bolt holes and the fluid go down by the case mating surface line. And that makes it looked like leaking from the mating surface. This is what happened to me before. I was almost going to disassemble the transmission to reseal but I didn't need to. I cleaned the breather cap that was clogged up, and then the leak completely stopped.

There are 4 rubber breather vents if that's what you mean and none are blocked, and even if one or two were then the others would take up the slack, I assume. I think it was just a poor job by me of properly RTVing the mating surfaces. I ended up draining the oil, removing the end case section, cleaning up both mating surfaces, then resealing properly with Ultra Black, and that section doesn't appear to be leaking now. There's still come leaking but from the innermost mating interface, which I'll have to remove the trans and take it apart to fix, but that can wait till spring. I'll just keep an eye on things and top off the oil now and then until then.

And, speaking of the breather vents, I think that one of them was oriented such that when I recently cleaned the engine bay with water and degreaser, some water may have gotten into the trans, which would explain the somewhat cloudy appearance of the oil when I drained it, kind of a dull and dark golden hue that was cloudier than the fresh oil I put in only a few years and several thousand miles ago, so I'll probably replace the oil as well.

Plus, since it was my first and only trans rebuild, I'm inclined to open it up to see if there are any issues. From day one after the rebuild there's been this weird noise coming from it that sounds like mildly excessive friction, like the sound a brake pad makes if it's a bit too tight even with your foot off the brake pedal, so maybe one or more shims are slightly too thick even though I did the solder test, or there's something else going on.