1996 Pontiac Grand Prix Recently Bought This Car Major Oil Leak Really Thinking

i recently bought this car and i have a major oil leak. i really thinking that its the rear main seal. it seams to be coming frorm behind the starter somewhere. my question is, do i have to pull the motor or tranny to replace the seal? i had somebody tell me that i coud access the seal by removing the oil pan? any tricks or helpfull advice will really be appreciated.