[BILT4ME]

I have had this problem on nearly every truck with a 4 speed in it. It's because the gearing is such that the truck spends most of it's life in 3rd gear. Towing, starting, stopping, etc is mostly in 3rd. Most folks only downshift from 4th to 3rd, and rarely to 2nd due to the granny low.

It has to do with bearing and gear wear and there is just enough that it allows misalignment.

I am fearing this EXACT same scenario on my son's 70 GMC K2500 that we're doing. Dropping in a crate engine to a worn transmission/transfer case.

I hope that's not the case, but if I was a betting man.........