1986 Chev 1/2 ton PU 350 700R4 Tranny

I'm having problem with Transmission leak at the oil pan I'v change the gasket three times, it leaking in the frt part facing the engine, I know it not leaking from the seal all that's new, and I lay down under the truck while it running, after I stop it start to leak more, even snug the bolts around the pan, I also try to seal it with silicone, how can I tell if it building up pressure to cause that or if the pan is bad. I'm lost please help. THanks

It is possible the pan sealing surface is distorted, take it off lay it down seal surface down on a flat sufrace and make sure it is not bent some, as I said, usually this is the problem.