08 Silverado 4x4

[NAMASafetyDirector]

So my truck started doing a couple wierd things this week. Has about 104K on it and just had the 100K service done with all the fluids etc etc. Anyway, back out of the garage the other day and made a sharp turn going forward and the rear end started chattering, looked back and the inside tire was ratcheting like I had posi. (was on gravel) ?? Then yesterday when I started it up after work directly after the engine fired the truck surged forward for a second. Not sure what's going on?? Any ideas

[CaptainMusky]

I am guessing you have the electronic locking rear diff. Hopefully the folks that replaced your rear diff fluid used the GM additive in it or maybe its specific fluid, cannot recall, anyways, this is important because otherwise they are prone to locking up.

I had a lot of issues with this until I swapped the fluid for the good stuff. Then again, my truck had well over 200,000 miles when I started having that issue, but it sounds exactly the same as mine.

I have had the "surging" thing you describe happen, but only when I turned the truck off. It bugged me, but didnt happen often and I never researched what could be causing it because I got rid of it shortly there after.