Severe Transmission Fluid Leak

So it becomes more severe when the vehicle is running? Definite shame on him for being dumb enough to ignore that fact. A leaking transmission pan gasket doesn't get worse or better when the vehicle is running. It stays the same due to the fact that trans fluid sits above the gasket at all times unless of course the fluid is low. I would agree with the pump gasket or more likely the main seal possibly being bad but I would first get the under side really really clean then put some U.V. leak detector in the trans fluid. Let it run for a minute with the cooling fan removed so it doesn't blow everything everywhere. Grab the U.V. light and play C.S.I. looking for evidence of where its leaking.

check the front seal that might be the problem.