1994 4x4 pickup Rattle/Growling noise

[atoyota4x4]

Seems like ever since I had a new clutch put in (and it was done by a very reliable place so I know it was done right) I have had a growling noise which sounds like it could be in the transmission. This mainly happens right after shifting from 3rd to 4th, but once 4th gear starts to wind out it goes away. You don't hear this noise during any other shifts. If I wind third out to about 3250 RPM and then shift to 4th, you don't hear it. Its only when shifting to
4th and I shift earlier than 3250 RPM's (kinda like the truch is under a load or the gear is to high for the speed I'm at). Did I explain that clear enough???

Anyway, I use to run 31" tires and switched back to stock rims and tires so I'm not sure if the truck got use to a certain shift point?? Would that make sense??

Anyway, when the noise occurs, if I lift on the gas, it goes away. If I knock it out of gear and rev the motor its not there. Seems like a tranny noise. Any ideas as to what is going on?