This one is driving me nuts. I have a newly built AOD that is shifting perfectly with no issues at all, except for a fluid leak from the outputshaft seal area. It leaks primarily while driving and shortly after driving. When I first get back from a drive, it will leave an 8" puddle in a matter of a few hours. Once it sits for a few hours, it lows to a very small drip. The output shaft is nice and tight with the yoke installed, so I doubt it's the bushing. I replaced the output shaft seal and that didn't help at all. I am headed to the shop today to put my newly rebuilt 9" 3rd member back together, so I'd like to try to clear this up while the driveshaft is down. The only suggestion I've heard so far is to make sure the drainback hole in the output shaft housing isn't plugged. That will require pulling the output shaft seal again, which is fine. My frustration with this even has me considering putting the new output shaft seal in upside down so the hole in the boot faces UP. At least it will leak a little less that way! Any suggestions on what to look for while I'm in there today?
Do those have a case vent? I'm sure it does maybe it's building internal press and the vent is plugged? Just something to look at!
Standard stuff to check: Is the centerline of the output yoke drilled? If so, plug the hole with silicone. When rebuilt, was the tailshaft bushing changed? If not, there may be enough run out in the tailshaft to pull the seal beyond it's useful diameter. Replace the bushing and seal. Was the seal installed with a thin coating of silicone? It may leak outside the seal if the seating area is scarred or pourous. Good luck!
I had that issue once and I found that my slip yoke had a pressed metal plug under the U-joint and it would leak there. I just welded it up fixed the problem.
The seal obviously works, since there is no leakage when the car is parked. There is play in the mainshaft, that oh so anoying bushing is worn out and needs to be replaces. Not a big deal really.
Thanks for all of the advise. I'll check all of these things when I get to the shop in a few minutes. My early theory is the slip yoke. It's brand new and I just slapped it on there...didn't even look to see if there was a drilled hole or loose cap on the end. There is no slop at all in the output shaft, so I'll save the bushing replacement for last. The vent or drainback hole might be a possibility, too. I'll report on the results when I get it squared away.
Slip yoke was fine...no hole. I replaced the output shaft bushing and output shaft seal. I noticed the flange for the output shaft seal had a decent sized bump/burr on it, so I ground it off and polished it. I also stuck a little dab of Toyota ****** sealer around the output shaft seal this time. Drive about 50 miles and only had a quarter sized puddle under the car this morning, which appears to be from my speedo cable hole. When my new speedo gear gets here, I'll probably put a small amount of sealer on that flange as well. Might have this leak down to a trickle before it's all said and done...
I was inclined not to post this because it makes me look like a dumbf$%k, but maybe someone else will learn from it and not make the same mistake. The main issue with my leak was that the ****** was overfilled by about a quart. I've always check my ****** fluid over the years by warming up the car and checking it with the engine running. I've been working on the car in the garage so much since this engine swap that it wasn't being driven much. Long story short, the AOD is very sensitive to being cycled through all the gears a couple of times after it's warm in order to get an accurate fluid reading. At full operating temperature, it would read about a quart low. If you put your foot on the brake and cycle it through all the gears 4 or 5 times while it's running (or drive a mile or two) it was reading overfilled. I picked up a $5 hand pump for a 1 gallon jug at Autozone, switched the rubber hose to the input side and pumped out about 1-1/2 quarts out through the filler tube. This was a hell of a lot faster and less messy than dropping the pan! Anyway, she hasn't leaked a drop since and I feel pretty stupid! Good thing is, I discovered a great way to get ****** fluid out without making a mess. This will come in handy next time I change the filter...
Thanks Dave wouldn't be surprised if I dont have the same. Mine drips a little too but not enough to worry about. Good to know this though.
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