I just swapped a trans from a 86 lg4 camaro into my 88 350 tpi Iroc. The swap went ok but now my trans leaks out of the vent tube but only after I shut it off. The trans does good enough for what it is especially with how hard I am on it but I can't go to the track with it leaking.

Before I installed the replacement trans I changed the filter and replaced the front and rear seals.When I did this the trans was on my engine stand upside down. Needless to say by the time I was ready to install it all the fluid that was still in the tranny had leaked out the vent tube.Did I hurt this tranny by working on it upside down? Or is it just overheating and pushing fluid out when it stops circulating?

 

About the only reason that a trans will leak out the vent, is because the pump is sucking air because the filter has a leak, and turning the fluid to foam.

I'd suggest taking a look at the filter gasket and make sure it's right.

 

Again it only comes out the vent when I shut it off. As long as it is running its fine. The pump cant suck air if its not running. Any help would be very appreciated.