Depends on the flex in flex plate.

 

So it may be flexing more at higher speeds which may be causing the noise? Just so I can get this tcase chain off my mind, is it possibly for it to make this noise on throttle if it was a little stretched? I ask because it is a similar sound to a stretched or loose cam chain on a four stroke dirt bike.

 

Have you checked the fluid level in the t case? and what shape its in? Also you could remove the rear DS and then the rear tailshaft housing of the t case and inspect the C clip retaining the rear bearing in place, and while you are in there install what's called a t case saver. The fsm should have a test for t case chain stretch you might look into it.

Edit: With the DS out check the pinion bearing.

 

Yes as stated previously, I just changed the t case fluid. It was good,no metal chunks or shavings. Ive heard of the tcase saver but wasnt sure if thaqt was for the back of tcase or where the front ds go into it. How would I check the pinion bearing? Just see if theres any up and down play at rear where the ds bolts on?

 

Thats a basic test yes, any chance this truck has a lsd in the rear diff? you might just want to pull the tire's, drums, the rear cover and have a look see what if anything is going on in there, look for metal chunks (part of the clutch disks) this is also a good time to check the pinion bearing a little better than just looking for side to side play.

 

yes it has lsd, i was planning on tearing into it and see how everything looked since these lsd are time bombs but was trying to figure out this noise first. Could it be the rear diff under load?

 

You never stated the general area the sound is coming from, like somewhere up front or rear, etc.

Based on your original post and some other comments, I'm agreeing with symptoms consistent with the LSD C-Clips going kaput.

The most pronounced I heard mine was slowly turning in a parking lot.

Have you done donuts in this truck? Burnouts?

 

Hard to say without being there but yes this could be the noise you are hearing and feeling.

 

It sounds like its coming from the front but if I move my 4x4 shift boot I can hear it like its below the middle of truck, could be echoing though so hard to tell.