I would start by changing the 75 cent O-ring on the distributor. They get hard and brake down after 100K miles. Then clean the area With brake cleaner. Could also be a rear intake manifold gasket (RTV) leak, or valve cover gaskets. Elimeate all upper rear engine leaks before jumping on the Rear Main Seal. Oil usually runs down hill. There is also a plate and gasket that covers the end of the cam, behind the fly wheel.

I have resealed my stearing gear box three times, first time lasted 30 min. second time 3 months. this time 9 months. Today I picked up a remanufactured box from Auto-Zone for $250. We will see.

Good luck on your search.

3 90 Trooper V-6's, 5 speed, 4.3L TBI, 31" BFG AT's, Fender Flairs, Bored intake, 1.6 roller rockers, MSD Coil, Jacobs Omni ignition. Heavy duty torsion bars, Rancho 9000 Shocks CAN'T SPELL, TO OLD TO LEARN, GOD BLESS YOU IF YOU CAN.