Transmission leak
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Joined: Oct 2011
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Transmission leak
My 70 turbo 400 tranny is leaking fluid. About a quart every few months. I thought it was the pan. So I changed the fluid, filter, and gasket. I straightened the small dimples in the pan flange and the pan is now sealing nicely. The fluid seems to be coming from the front of the tranny. The car sat without being started for almost 30 years. When the motor was out of the car recently, I had changed the front transmission shaft seal so I don't think it's that unless I bought a bad seal. The fluid seems to leak when the car sits and I don't see any drip trails when i drive the car. The leak is somewhere in the front of tranny as it is leaking thru the flywheel inspection cover and onto the very front of the tranny pan. Could it be the front cover gasket? When i pulled the inspection cover off and looked inside, there was no obvious leak. Any ideas of what I could do or check short of pulling the tranny and sending it out for rebuild? Steve
Le Mans Master
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From: Gladstone MO
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If you replaced the front seal, did you also replace the pump bushing? It's really rare for the front pump gasket to leak- there's a paper gasket and an o-ring, plus all of the bolts have seals on them.
When you replaced the front seal, did you pack the cavity on the back of it with grease before you installed it. There's a small spring around the OD of the seal lip that is easy to dislodge when you drive the new seal in.
When you replaced the front seal, did you pack the cavity on the back of it with grease before you installed it. There's a small spring around the OD of the seal lip that is easy to dislodge when you drive the new seal in.
Thread Starter
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I only replaced the front and rear transmission seals. I did not replace the pump bushing (is that something I could have swapped out without taking tranny apart)? I did not pack the seal with grease. I put the toque converter back on the transmission right before bolting the assembly onto the back of the motor. Is there anything I can look for or check/replace without taking the tranny out of the car? Thanks, Steve
Le Mans Master
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if the seal leaked before, its usually caused by to much play in the bushing or old age, grease wont fix that. the front pump needs to come out to replace the bushing. given that it probly needs replaced, might also be a good time to rebuild the front pump.
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Thanks. Sounds like I have no alternative except to pull the transmission. I'll do that in the fall and have it rebuilt. Anyone know of a good transmission shop that works on these old turbo 400's in the Boston area?
