mark kibort

I talking to someone that has a Manual transmission that's leaking, possibly at the front seal (out the torque tube, 5th gear coupling)
can that seal be replaced by dropping the torque tube and replacing it with trannie on the car?

Randy V

Ask GB.

He's working on my car now and needs to drop the auto trans to replace the front seal.

mark kibort

I think its the truth... i cant imagine... lots of work just to keep it from leaking. wonder if there is stop leak products that can work. does dyno oil vs synthetic leak less? (sweptco vs redline, mobil )

The Forgotten On

Dyno oil will leak less due to having larger less uniform molecules than the synthetics smaller uniform ones to put it simply.

GregBBRD

Manual transmission=Yes.

Automatic transmission=Completey different thing. The torque tube attaches to a bell housing which contains the rear flexplate, torque convertor, etc. All that stuff has to be removed to get at the front convertor seal, which seems like they never leak. The leak is usually from the front pump "O-ring"....which requires disassembling the front of the automatic transmission. In short, the transmission needs to be removed to do virtually anything.

GlenL

How? I can see separating the tranny, disconnecting the mounts, and pushing it back but is there enough room to do the seal? Or does is the TT removed?

GregBBRD

I can put Mobil 1 into freshly rebuilt tranmission and it will not leak past the seals. Anything else you want to put into one of my rebuilt transmssions is OK with me....just don't call me when it leaks.

Redline leaks 100% of the time, as do other synthetics. Draining this stuff out and putting in Mobil 1 generally will stop the leakage after a few miles....so the seal isn't actually damaged.....it just can't seem to properly seal.

New seals have a very "sharp" edge (almost like a "V", in cross section.) It seems like once this "V" gets flattened down some (wear), you can then use some of these other synthetics. Perhaps the sharp "V" of a new seal is too sharp and the "better" synthetics are so slick that the new seal can't get a "bite" on the shaft....

I don't really know why....I just know what leaks and what doesn't leak.

GeorgeM

Mine leaks out of the front seal with Redline, so I'm willing to swap it out before tackling that job.

Are we talking Delvac or LS?

Thanks!

GregBBRD

LS

mark kibort

sounds like almost as big of a job to remove the torque tube as it is the entire transmission. when bill and i did my trannie we took the transmission and TT out as one unit. but it required his special socket wrench for the 4 bolts at the bell housing. i guess if you do that, and unbolt it at the transmission and maybe move the trasmission rearward , it will drop down and you can get that seal? still a lot of work. UGGG!

ever since i replaced that top cover gasket, i havent had any leaks. there is still a lot of moisture around the front drain plug, but no leaks with redline
however for our pal with the leak, and the information ive heard about the dino oils, wouldnt swepco be a good place to start? my only experience with synthetics back in the day, was with engine oil.. it leaked a lot when i changed to redline engine oil as my first exposure to synesthetic. smaller molecules??

GregBBRD

No idea. Way beyond my pay grade.

I avoid the entire oil debate on both engine and transmssion oils....it quickly becomes just a posting of whatever whoever just bought and used....without any qualitative or quantitative data.

I've got a good friend who is trying to figure out what to do with the Boxster oiling systems. They have a serious oil ejection and pick-up uncovering issue at higher rpms. Because they measure the oil pressure in the worst possible place (not at the best possible place like a 928) oil pressure fluctations on the gauge are much more visible. He had some great theories about what is happening at the oil pick-up as the air from the pistons moving hits this area. Anyway, he build a plexiglass cover for the sump, so he could actually see what was happening. (Pretty simple to do, on a Boxster engine, because they have a large lower plate that bolts on.) Answered a lot of questions. The oil in the sump turns into a milkshake at 5,000 rpms....just a giant whipped up mess of brown foamy oil. It's not that the pick-up is actually uncovered and sucking in air....the air is mixed in with the air....lots of it! (Of course, this is a static test....no idea what happens with G-forces.)

Supports your idea that an oil that has more anti-foaming characteristics is going to work better.

I think I'm going to do this on a 928 engine, just for giggles.

mark kibort

Yep, im in the same boat here. i have no other information than my own anectotal evidence. a handful of oil changes with each of my varied 928 gear boxes.. the all leaked or seeped a little. i like the large molecule theory, and used that back in the day for my decision. But, i have had no issues with redline so, its what i use. im sure others are just as good.. maybe better.
I do trust what you have seen, in greater numbers.

as far as the engine oil foaming... wow, thats scary stuff. makes you wonder why more engines dont grenade at the track.
I would be very curious to see if amsoil could fix that. is that guy willing to try it? 20 /50 racing oil is what i use. (if you do the test).
I will tell you that when we had the oil pressure issues with the 79 with mobil 1, the dipstick looked full of bubbles. i always checked the 928 after a session, and its always smooth as silk with no bubbles. funny, if that solved the issue. maybe the 928 with the way the crank if flush with the bottom part of the cradle , the crank doesnt get to whip the oil as much? how cool would it be to actuallly see whats going on in the pan, and on the track too!

GlenL

Jezus, Mark, I can't believe it!

You should know that Amsoil hasn't made the 20w50 in years! The Dominator racing oil is 15w50!

My dealer kept finding quarts and gallons in his warehouse/garage, and saving them for me, for a couple of years but it's all gone now. The new stuff has the same solid oil pressure when hot and that unusual smell.

GregBBRD

I did tell him about your results with Amsoil and he did try it on the track.....but I don't think he tried it on this particular test.

I'll check and see.

mark kibort

ooops! you are right! i wonder if there is a real difference. how can they control fluid manufacturing to such close tolerances. and how do they make it smell and look like liquid strawberry Jello.
Yes, DOMINATOR 15/50! I think the ordering code is RD50