# Persistently annoying transmission leak - any thoughts?



## SixTeight (Apr 24, 2011)

Last weekend I decided to tackle the three leaks on the GTO, one of which was from the oil pan, another from the transmission pan, and the third from the back of the transmission where it connects to the driveshaft.

I'll score myself a 67% on this one, because I cannot get the the third leak to stop for the life of me.

There is a circular gasket that tightly fits into the hole in the rear of the transmission casing where the spindle is that bites into the driveshaft and transmission fluid is slowly but surely leaking out of it (about enough for four or five drips on the garage floor if I leave it parked for a day or so).

The gasket that was in it looked fine from the outside but, nonetheless, I pulled it out and replaced it. The casing itself also looks fine, with no gouges or cracks.

The new one fit in snug, but it leaks just the same... all over my beautiful garage floor.


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## Joe C2 C5 (Apr 13, 2011)

Did you look closely at the surface of the yoke where the seal rides to make sure it doesn't have a grove worn into it? The seal may not be able to make a close enough fit to prevent the leak.


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## dimitri (Feb 13, 2009)

Joe C2 C5 said:


> Did you look closely at the surface of the yoke where the seal rides to make sure it doesn't have a grove worn into it? The seal may not be able to make a close enough fit to prevent the leak.


:agree:agree:agree:agree:agree:agree:agree

Also while your at it might as well change out all of the o-rings/gaskets. 
There are two for the speedo, one for the dipstick, one modulator, tail shaft housing lip seal. I think that is all of them. They are real easy to replace.


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## pontiac (Mar 6, 2011)

yoke should be super smooth and seal should be greased (with white grease) initially when yoke is first slid in. Also the seal in the trans housing end can be sealed with gasket sealer (although not usually necessary) like permatex no. 2. Lastly, some yokes actually have a pin hole in the base which can be opened and leak trans fluid. look inside yoke at the bottom and confirm it does not have a casting hole.


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## Thumpin455 (Feb 17, 2010)

Well the USAF calls it a leak if it drips more than 3 times per minute. I know what you mean about it being a PITA leaving spots on the driveway/garage floor. Depending on the transmission you have, it could be the rear bushing being worn. If it is worn the yoke will not be centered in the seal, and it will leak around the edges of the egg shape that condition creates.


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