grinding when in 4x4

[dranger21]

I have a 99 that i just had the transmission basically rebuilt in. Today I was on my way to camp and decided i would try the 4 wheel drive to make sure everything was ok with it still. Well i shifted into 4hi at about 5-10 mph and then heard grinding coming from the transmission/ transfer case area. It worked fine before the transmission was replaced so now i have no idea what might be wrong. I have the 4r44e transmission and on my bill it said 5r55re and i was assuming that was just punched into the computer wrong because i figured the parts werent interchangable but I have no idea. If anyone has any clue what could be causing this to be happening i would really appreciate the help.

 

[Rifleman]

Well, if the old transmission was rebuilt, it had to be out of the truck (along with the transfer case). I'd say they didn't get something connected properly or the electronic shift servo is failing.