I have a 85 extra cab 4x4 and manual with a one piece driveshaft. I thought all 112 inch wheelbase had the 2 piece design. Any idea where this driveshaft may have came from? It’s a salvaged truck.

 

Whether it's a standard cab or an extra cab, or whether it's a 102 or 112 inch wheelbase doesn't seem to be the determining factor in driveshaft type. According to "How to keep your Toyota Pickup Alive" page 277, it depends on whether you have the short bed or the long bed, even on the 4x4 models. Source: https://toyotachinook.files.wordpres...ckup-alive.pdf

If your truck is a short bed the one piece driveshaft would be correct. If it's a long bed there's no telling what that driveshaft is or where it came from, unless you can find the guy that put it in there.