oil gushing out rear main seal

I have a 89 f150 5.8,c6automatic with almost 200.000. Its got oil flowing out the rear main.which is easier drop the tranny or pull the motor,im leaning toward tranny drop, if I drop it would it hurt to replace the fluid and filter in it, as it has that many miles the trans shifts fine however. also since i noticed this leak the oil pressure goes to nothing at a stop in gear then after it blew naturally it was dropped at a idle think the seal will cure that,as its gushing now would a test be accurate or should i just put a new oil pump in while she is down? The motor runs like a champ dont burn oil plenty of pickup,no chatter when gauge dropped either. I just dont wanna keep tearing it apart all winter in the -5 wind chill weather is why ive got so many questions. thanks for any help