Try the search function for information on swapping out the third member of your truck, there is a lot of info available. The third member (also called the "pumpkin", "chunk" or "carrier" (because it carries the ring and pinion gears)) is called the third member because it is the third member of the drivetrain: the engine, the transmission and the ring and pinion carrier. Rearend usually refers to the complete housing and carrier.
There are quite a few junkyards around this area that have some older trucks, but a lot of them are being crushed since the price of scrap metal went up so much. If you are going this route, I'd start looking soon.
Larry
