Im assuming that you have the 4spd sliding gear transmission with granny low.
That transmission is a very simple transmission to rebuild.
I just rebuilt mine myself and was amazed at how easy it was. All of the bearings are still available from NAPA,
and most of the other parts can be found on E bay, either used or New old stock
The gasket kits are available from Jim Carter.
The easiest way to find the parts it needs, is find yourself a GM parts catalog that covers that truck, as long as you have the original GM part number, you can find what you need.
The bearings also have the numbers stamped on them, and NAPA can cross them.
Last edited by JeffL; 07/23/2017 2:43 PM.