Still a Slight Tranny Fluid Leak

**GULLETT17** · 01-03-2008, 11:42 AM

Hey fellas. I just got my tranny back from the rebuild a few weeks ago, and it's still leakin from the rear seal. Not a lot . . quarter size spot on the pavement between drives. It was leaking there before the rebuild, I was unaware of it, fluid got quart low, and this is probably what caused 2nd and 4th gear to go out. I'm no tranmission expert by any means, so I was wonderin what you guys would check for that could be causing this. Maybe my driveshaft is out of balance or has a worn slip yoke? (with only 74000 miles though??) Should I go ahead and just change the seal again?
I'll have her up on the lift this w/e to put my new exhaust on so hopefully I can kill two birds with one stone!

**Firebirdjones** · 01-03-2008, 12:18 PM

If you have replaced the seal in the past and it still leaked then you most likely have a tailshaft bushing problem.

Both the bushing and the seal work together to keep that trans fluid in there. Any play in the bushing and the seal cannot do it's job.

Was a new bushing installed during the rebuild? You would be surprised at how many shops don't replace all the bushings if they don't see a need to.

Check the bushing for any nicks, grooves, unusual wear spots etc....also check the yoke on the driveshaft as well. I like to take a mild brillo pad or scotch brite pad and go over the entire surface of the driveshaft yoke to make sure you have a nice smooth surface for the bushing and seal first.

Then remove the tailshaft housing,,,knock out the bushing,,,install new bushing being carefull not to nick it,,,,bushing install tool is good to use here. Install new seal and reinstall tailshaft housing.

After reassembly check the inside diameter of the bushing, and the outside diameter of the yoke,,,,there is a minimum and maximum clearance. If the clearance is excessive, your driveshaft yoke has excessive wear and needs replaced. After everything is within spec, rub a liberal amount of vaseline on the yoke, the seal, and the bushing,,,to give everything a chance to live those first few miles. Don't worry if you get vaseline inside the trans,,,as it will dissolve as soon as transmission fluid hits it. Hope that helps.

**Chaos** · 01-03-2008, 12:34 PM

Not sure on the A4 drive shaft, but on my M6 drive shaft, fluid was leaking out of the drive shaft front yolk itself, where the yolk mates to the input splines on the shaft.

**GULLETT17** · 01-03-2008, 12:56 PM

Thanks guys! I'll put the car up on the lift and check all of that out probably tomorrow night and give yall an update. . . I'm pretty sure the tailshaft bushing was changed, but i'll call my tranmission guy tonight or tomorrow and ask him for sure. Thanks again!

**GULLETT17** · 01-17-2008, 05:42 AM

UPDATE : i havent have time to take the drive shaft out or change the seal or bushing yet, but i talked to my dads friend, who has worked on driveshafts for many years. He said that it could just be the vent plugged up and causing enough pressure to blow tranny fluid out the rear seal. . . thoughts?

**Firebirdjones** · 01-17-2008, 08:17 AM

Originally Posted by GULLETT17

UPDATE : i havent have time to take the drive shaft out or change the seal or bushing yet, but i talked to my dads friend, who has worked on driveshafts for many years. He said that it could just be the vent plugged up and causing enough pressure to blow tranny fluid out the rear seal. . . thoughts?

Well it's possible though I have never had that issue. I'm not sure what would plug it up but it's easy enough to check.

I believe the transmission vent comes down with a piece of rubber hose connected to it towards the driver side,,,and is secured to the torque arm with a small clip,,,,thats how mine is.

**GULLETT17** · 01-17-2008, 09:23 AM

i dont know what would plug it up either but that would definately be an easy fix. . . well see what i find out this weekend. i don't know if it could of gotten mashed shut when i put my tranny back in? its a possibility. . . I'm just ready to fix this little issue so I dont have to keep such a close eye on my tranny fluid level!

**GULLETT17** · 08-22-2008, 10:09 AM

update and new issue: the leak has been very slight since i started this thread. . .ive had to put prob a half quart total in since january. . . but today as i was leavin for lunch, i noticed a large spot (ft wide) under may car. . .i check the fluid and its real low now. . . what the hell happened? im buyin a new bushing, rear seal, filter and gasket on my way home (as well as some fluid!). hope i didnt hurt something.

**GULLETT17** · 08-25-2008, 11:49 AM

Well pan gasket was shot, must have tighted it too much

. . . changed it and filter, and changed both the rear seal and bushing. . . i haven't seen any spot under the car yet!! so hopefully its fixed!! finally!!