My 1971 Pantera has an oil leak at the back of the motor. It only leaks when the engine is running. When I come back from a 5 mile test run it makes a 6 inch puddle on the garage floor. Once cleaned up there is no oil leak and thus it looks like it happens due to oil pressure. I have seen this problem before with an improperly sealed oil gallery plug. If that's the case on my 71 Pantera can I fix it by just pulling the transaxle and bell housing? Or could the problem be in rear main seal which probably requires pulling the engine?