I need to change my transmission

The cheapest rebuilt 18spd I have found around here is 5500, with a core, which that auto would not work for one, add new clutch and driveline to match, and you are close to that number just for parts.

 

How many speed tranny? A 10 speed can be converted pretty cheap and easy I think. An 18 will require a different case, a gear or two and sliders. I converted my 01 Pete from 18 speed autoshift to 18 manual. Switched most of my internals to different case. Bought a used shift plate and tower and away I went. Some where between 2 and 3k I think I spent. I pulled and replaced transmission myself. Had shop do the rest of the work. You most likely have a solo self adjusting clutch, replace it, they are junk.

Inland truck parts did the tranny work. They have many locations