4 Spd slight grinding when shifting.

First off, a '65 MOPAR trans is a ball and trunion and doesn't use a bushing, it uses a rear bearing, seal, and bolt on yoke. Second, I'd check the fluid level and the type of fluid they might have put in it with the "bushing" change. Sounds like it's about empty. Just things I'd check first. Hope it's something simple, it can get expensive. Good luck. Russ.

That's where I'd start, right there.
Fluid level and viscosity.

The hint was "worse when it warms up"