Leaky transmission pan

[Kimper]

I have a 76 Chevy k10 with a turbo 350 in it, my problem is I can't get the tranny pan to stop leaking. I have pulled it off cleaned it and reinstalled it with just a rubber gasket, rubber gasket with RTV, and plain RTV and every time it leaks. I have looked at the pan and it seems straight but I am not 100% sure. Can anyone give me some advise.

[Dr_Snooz]

You want to tighten the nuts in a criss-cross fashion to 8 lb-ft. That's about wrist tight. It's well worth investing in a torque wrench to do it. If you've over-tightened, replace the gasket with a new one.

[Kimper]

Would you use a rubber gasket or a cork one??

[bd]

Chances are the pan flange and bolt holes are distorted.  If distortion is not excessive, the pan can be straightened with a small ball peen hammer and mallet.  The mallet can be used to pound the flange straight by supporting the back of the flange against a suitable wood or steel workbench along its edge.  Then fit the ball of the small ball peen hammer against the bolt holes and use the mallet to drive the ball toward the holes to slightly invert the holes away from the sealing surface of the transmission. 

Cork gaskets were original equipment.  As Dr_Snooz posted, either should work if you don't overtighten the bolts.

If you absolutely cannot get a good seal and you are sure the pan gasket is the culprit, a cast aluminum pan should solve your dilemma, but at a hefty price.

[enaberif]

I have a 76 Chevy k10 with a turbo 350 in it, my problem is I can't get the tranny pan to stop leaking. I have pulled it off cleaned it and reinstalled it with just a rubber gasket, rubber gasket with RTV, and plain RTV and every time it leaks. I have looked at the pan and it seems straight but I am not 100% sure. Can anyone give me some advise.

How are you sure its the pan that is leaking? TH350s can leak from so many dang places that it may seem like the pan especially with blow back that its very difficult to find the source.

You could have a pump seal, front seal, fill tube, speedometer, or even the shifter linkage leak on you. You need to check out all these things before really thinking its the pan.

[Kimper]

Because it leaks until it gets just below the pan, then it doesn't leak anymore.

[enaberif]

Because it leaks until it gets just below the pan, then it doesn't leak anymore.

Hmm I don't quite follow. Care to explain?

[Kimper]

It leaks until the fluid get below where the pan meets the transmission, then it seems to stop..

[gregmc30]

I had a major transmission leak and pour in 1 bottle of Trans X Slip Stop and Leak Fix. It stopped my leak after a few days. $7 at Oreillys. Great stuff.


Sent from my iPhone using Tapatalk

[Dr_Snooz]

I like rubber gaskets. They're much easier to remove later.