Rear Main Seal

My Rear main seal has begun to leak oil in my 340 not leaking much but a nusiance. I put a quart of Bars leak rear main seal stop leak in and its still dripping oil. A lot of people told me they swear by this as it has worked for them. My question is how much of a job is it to replace this seal? I was told that all I have to do is to unbolt the tranny slide it back, without dropping it,(its an automatic) and the seal is right there.I was also told that I have to drop the pan, un bolt the rear main bearing cap and there is where the seal is. Just want to make sure before I begin to tackle this. Probably would be a lot easier doing it on a lift but have to do it old school