Grinding /roaring noise in 2hi

[raindancer]

my 1995 GMC Z71 is making a grinding noise on acceleration in 2hi only. I've drained & replaced all drive train fluids, everything looked clean. whats my next step? The truck has a 350, 5 speed granny low, with an NP241-c transfer case.

[DaveH71]

Wait so the sound go completely away in 4hi and 4lo?

[raindancer]

Yep, no matter how much you gas it.

[DaveH71]

Common problem with those transfer cases, there is a lock ring on the output shaft of the transfer case. This lock ring breaks and lets the gears mash together inside the case. Pull the rear drive shaft and then pull the tail housing on the back of the transfer case and you will be able to see it.

 

 

There was a permanent fix developed for this awhile ago but i haven't seen one of these transfer cases in awhile so you might wanna see what you can find on google, or just replace it with another stock part. If you can don't drive the truck because if this is the problem it will cause damage. At least drive it the least amount possible.

[raindancer]

I'll take it apart tomorrow & have a look. I have a t-case & front & rear end to go on it but I wanted to wait till after deer season to tear it all down. this points me where to go next, I appreciate it! I'll post to let you know what I find.