Rear main seal

I put new brake pads on today and when i went to put the jack under the truck i noticed there was a drop of oil on the floor when it had only been parked for less than 5 mins. So after i changed the pads and all i wiped down the whole under side of the engine and took it out for a lil spin. Near as i can tell the oil is leaking out between the tranny and the engine which leads me to believe its the rear main seal. Still I need to clean the whole engine down completely and check to see for sure cuz it could be leaking out of the back of the intake. But anywho i can only imagine that that seal is a major bitch to replace, having to remove either the tranny or engine. However, sometime this summer i do plan to buy an HD rebuild kit for my tranny. Also the engine itself could use a rebuilding but i didnt plan to or even want to do that any time soon. So im thinking the gooderest idea would be to remove the tranny whenever i build it and then try to get at that seal....sound like the best plan of attack?????

Boo!

that's a 1 pc rear main seal the only way to change it is to pull the trans or motor.