Went for a short drive last night after replacing the serpentine belt. Heard some squealing when I gave 50% or more throttle. Couldn't see anything wrong on a quick look around. Went out again and everything seemed normal. This morning I pull out of the driveway and had squealing right away, very little throttle. Also felt like the diff was locked up(hopping).

The truck had been sitting for a couple of days. Hasn't been driven hard for a week or two. Did hear/feel what seemd like a loud bang a couple of weeks back during some heavy wheel spin, but everything still seemed to be operating as it should. Checked the log and I wasn't near the rev limiter yet.
Thought maybe it was the spare trailer tire I had in the back.

So tonight I lifted up the rear, put in neutral, and spun the rear wheels by hand. Both axles seem solidly locked together. No Play at all. Can't budge one if somebody holds the other. There is no noise when I rotate the wheels in reverse, but there is a squeal from the T-Case when I turn them forward.

What do you think?

Here's the squeal http://media.putfile.com/T-Case-Squeal

 

Sounds dry as a bone... nothing a lil lubrication can't eliminate. Ole country-boy wd40 mentality'll lick dat. Unless the noise is INSIDE the t-case.

 

Damn that doesnt sound right with jesus at all!

 

You sure it's the t-case and not the u-joints?

 

That 's what I was trying to tell myself but it seems more like the t-case. Only does it in one direction. Sounds just as loud at the front as at the back of the t-case.

 

Just crawled under there again. Seems to be coming from the trans output/t-case input area. Goes away if I put the t-case in neutral. Definitely not u-joints.
Could even be the trans.

 

Weird....I got nothin else for ya....sorry....

 

Do you have the Automatic Transfer Case? You will have a 4 button switch in the cab and the top button will say AUTO 4WD. If so check the level in the T-Case and make sure that you have the blue Auto-Trak II fluid from GM in there. It might not hurt to change the fluid and see if the noise goes away. If you have the Automatic Transfer Case only fill it with the blue Auto-Trak II Fluid from GM.

 

Yes it is the auto t-case. Fluid was OK and the right colour. I was going to change the fluid before taking anything apart. Read that fluid contamination can cause some issues. Not overly optomistic about it though.

Just got a call that my Tru-Trac is in that I originally ordered back in May or June! Finally got around to doing a follow-up a few weeks ago. Just a tad to late.