I noticed a couple of drips of oil a few months ago in my driveway on this truck. It is a '92 4.9L Auto 2x4 with 79k. The truck has been driven 4k in the last three years. Now that I am using it as an everyday driver, the leak has gotten considerably worse. I've been adding approximately a quart of oil every 3-4 weeks.
Looking underneath, there is oil covering the pan. What is the most likely cause of this? How hard of a fix would this be for a relative amateur mechanic?

Thanks
Don

 

rear main seal most likely

look under the truck and if you see oil dripping from around the bottom of the bell housing or down by the starter, that is a tell tale sign...

if its leaking from the front of the engine, thats probabally the front main seal

the rear is a pretty cheap and / or easy fix, you have to drop the tranny tho

 

If there's oil on the pan, it's coming from the front, and as mentioned, is most likely the front seal. Also check the pushrod cover on the drivers side of the block, behind the distributor.