1) Two piece seal.

2) Can't be replaced without removing motor.

3) A "Redi-sleeve" is used to provide a new sealing surface on a scored
shaft. It cannot be used for a rear main problem since it is one piece
and won't pass by the flywheel mounting flange.
Ted wrote:

Hi,

I have a 1986 3.7L inline 4 cyl by Mercruiser. Just had all 3 bellows
and drive yoke replaced and now it appears I need a new rear main seal
on the motor (I know these aren't related repairs). It's leaking oil
out the back above the oil pan. Has anyone done or had this repair
done to theirs? I've worked on a few car motors and have friends with
extensive car motor rebuilding experience, and thought of possibly
tackling the job myself. Is the rear main seal a two piece or 1 pc on
the 3.7 Merc motor? Can the seal be replaced without motor removal?
If you paid to have this done, can you give me a ball park figure on
price, and other common repairs done with the seal?
Someone mentioned a "ready sleeve" to repair crank shaft sealing
surfaces.

Thanks
Ted