How hard is it to replace the rear main seal on a 2004 GP. Is it possible to do without pulling then engine/tranny? I didn't notice anything until last night when I lifted the car on the jack to do my front brakes. When the front was lifted, a bit of oil was leaking onto the ground and appears from between the engine/transmission. I was told by a friend its most likely a rear main seal, but that he didn't think that had oil against it? Anyone else have an opinion on what it could be?