Hi Bob...G'day!
What you've asked is possible, however it is a stretch and only up to a point. To replace the rear main seal you will have to remove the transmission, the oil pan and you'll have to drop the crankshaft assembly down as much as possible...leaving it in the engine, naturally. Even then the work will not be easy and possibly only divine providence will assure you of solving the leaking. Difficult at the best. The clutch plate can be replaced while you have the transmission removed. It would be a good idea to look at the flywheel and be sure there are no burned spots, rough spots, checking or glazing. If so, you need to remove it and have it professionally resurfaced. The okie bushing can be replaced with the rear end and all in place as I remember...might be easier with the rear end removed. It would give you more room to work. Good luck!
