Over tighening is by far the biggest issue. When I show people how tight they should be they tell me no way will that seal. These are the same people who say they will not seal. The pan must be flat. I keep a body dolley in my hammer draw just for fixing pans. Seems like the only pans I do not have to fix are the factory installed ones.

A thin coat of Vaseline on the gasket help keep the gasket from drying out and seal small inperfection. But if you over tighten the vaseline will help the gasket pop out. I would be lyeing if I said I never had a comeback on a transmission repair but I can not remember a comeback for a pan leak.

If you put ANYTHING on the gasket beside vaseline besure if is OK for automatic transmission use or you give it more then enough time to fully cure. Even in small traces some very common chemicals will trash your transmission.

 

ahhh,thats 150 INCH POUNDS on the pan bolts.and use a criss cross tightening pattern

 

transmissions can be a pain,for sure.you cant go wrong buying and using a inch pound torque wrench for these things.