why are the transmission breather vents pumping gear oil?

zentoad · #1 (**permalink**) 06-11-2008, 11:14 AM

Had the engine/tranny out, so you know it was hanging at an extreme angle... Is oil coming out of the tranny because it all loaded up at the top rear of the trans? OR what else?

Was not overfilled, at least it isn't now. I assumed it would stop once the gear oil dropped back into the case. Don't have a whole lot of miles on it since reinstallation, but it is still leaking.

Any suggestions would be greatly appreciated.
Feel free to tell me where to look, while I search for the info that is probably already posted.

Thanks

**Tifosi** · #2 (**permalink**) 06-11-2008, 11:23 AM

To bounce a couple alternative ideas:

It's not a result of that tilting you mentioned letting oil pool in the shift tower boot and making you think it's coming from the breathers is it?

Is the rear seal in good shape? (you might be seeing flung stuff if it isn't, which again could appear to be coming from the vent area)

All the funny washers and such on the shift lever stub assembled in the proper order?

Trans case studnuts tight?

zentoad · #3 (**permalink**) 06-11-2008, 11:42 AM

Not sure if it is the breather vents or the tower shift boot at this point. Oil is dripping off the rear crossmember. The rear seal looks OK. When I look up at the tower from under the car I see oil on the bottom of both breather vents housings... could be from the shift boot I guess.

I don't think that I have installed the small seal around the shifter as seen in a picture in another thread. When I dissassembled it, the seal was broken and, if the picture I saw was correct, installed in the wrong spot... ON TOP of all of the other funny washers...

Is it supposed to be UNDER the smallest washer, with a hose clamp on top? I think that is what I saw in the picture... I will have to go and find that again.

The way it was installed I didn't see how it could be accomplishing anything... and left it off....

Sad part is...( that is an understatement ) ... I just glued down a new carpet on the trans tunnel.... (insert expletive here)

zentoad · #4 (**permalink**) 06-11-2008, 11:49 AM

Here is the picture... thanks Ossodeseppia...

if this is correct... you may have pointed me in the right direction Darren...

and I have no reason to think that Osso would steer me wrong...

I'm guessing the hose clamp is just temporary and that the shifter will hold everythng together...?

**Tifosi** · #5 (**permalink**) 06-11-2008, 12:11 PM

Correct, that clamp would be removed and the shifter would hold the stuff together. (and yes, the seal goes in as shown in the pic)

The carpet shouldn't be a big deal should it?

I mean you'd be working with the hole in the tunnel that the shifter comes through, so once the boot(s) are removed, there should be more than enough room to work without messing with the carpet. (or is there something special about the tunnel in yours that I'm not aware of?)

zentoad · #6 (**permalink**) 06-11-2008, 12:26 PM

following picture is not my car... but shows how the carpet on the tunnel covers the shift boot "tower" flange... the mounting screws are under the carpet.

Darren, do you, or anyone else, have an idea weather the fact that the tranny was tipped at an angle is the main factor in this leak?

Or, do you think it would be leaking anyway even if the tranny weren't tipped back to that extreme angle?

Joe Papa Sr · #7 (**permalink**) 06-11-2008, 04:17 PM

Zen,

dont know if this is relevant, but just did my trans/gears....and learned that oil seeps from inner shift boot, pretty much, to create a oily mess below car, as you look up toward those 2 breathers, suspicious of them. I think the bigger culprit is the seal that the inner (not outer) shift boot makes, around the tower top, where the boot edge contacts the alum alloy tower.

I did 2 things:
1) I sanded smooth the circling surface edge which would contact the inner surface of the inner shift boot.

2) cleaned v well, ther inside of boot, AND trans surface, with acetone.
3) applied a coat of aviation, mil spec sealant to both surfaces, waited 15 min, and put on boot, and clamp.

If you skip the smoothening /sanding of the tower edge, with 100 grit, the sealant wont seal well, as this surface is left as raw casting.

zentoad · #8 (**permalink**) 06-12-2008, 05:30 AM

Yeah, I was suspicious of the inner shift boot as well. When I had it apart I installed a beefy hose clamp in place of the zip ties and safety wire i found there. But I didn't do any sanding or apply any sealer. That sounds like an excellent idea.

Joe, is it common for the inner boot to make a mess even when the small rubber seal discussed above is installed correctly? More accurately, I guess I'd like to know if the seal was in place on your car when the boot was leaking?

Or was it a pre-emptive strike on your part?

Thanks for the feedback guys. I'm gonna have to remove that carpet and find out what is going on...hopefully reinstalling the carpet will be easier the second time. I had a fun time trying to get it installed with no wrinkles the first time around.

Joe Papa Sr · #9 (**permalink**) 06-12-2008, 09:22 AM

Well, dont claim to have vast experience in this, just a litle. But, yes, that seal on top was in place, but in my opinion, doesnt mean a thing, as some designs are just better than nothing (like the inner shift boot, contacting a surface left rough with casting finish, instead of machining it). I suspect, although difficult to verify, that oil sloshes around so much, some jumps through the top, through that seal. But that seal has to stay free to slide around, based on design logic.

BUT I believe that inner boot surface will help, if done right. Man, I just finished that trans project, with acetoneing (a word?) the contact surfaces on the case, then use aviation sealant, torque to specs, and after a month, guess what..........leakage. Sometimes, it makes one just want to give up.

Joe Papa Sr · #10 (**permalink**) 06-12-2008, 09:24 AM

Oh, as of now, so far, I dont see any leakage from the work Ive done on that inner boot area. But that leakage, apparently, is from the case area where it meets the bellhousing. And some bolts.....

Rich · #11 (**permalink**) 06-16-2008, 07:02 AM

Hi Tony,

Did you add the oil to the transmission before you installed it in the car? Do you think you over filled it? You may want to try to open the filler plug and see if any oil comes out due to over filling it.

Thanks
Rich

zentoad · #12 (**permalink**) 06-16-2008, 07:13 AM

Rich,

I did add the oil before installing it. I checked the level after the leak became evident and it was not overfilled.

Haven't had the chance to inspect the inner boot on the tower yet...

Thanks
Tony

Rich · #13 (**permalink**) 06-16-2008, 07:35 AM

Hi Tony,
Another thing you can try, check the vents/breathers for blockage and check the three drain holes near the washers and make sure they are clean. You should get some oil up on the washer and they should drain back into the transmission.

Rich

zentoad · #14 (**permalink**) 06-16-2008, 08:47 AM

Thanks Rich,

I will do that. It helps a great deal to understand how things SHOULD work.
The drain hole thing I didn't know about.

Andrew · #15 (**permalink**) 06-16-2008, 09:22 AM

For the three drain holes to work, the boot needs to fit well and be clamped tightly around the shift tower. Otherwise the oil leaks down the side of the tower.

The trans when turning basically acts like a giant oil pump, so it doesn't surprise me that oil finds its way out the top. On race transmission with "standpipe" vent hoses to the overflow bottle at these vent locations, oil will get pumped way up the hoses from the pressure.

Andrew