First time post. Here is my problem.
2005 silverado Z-71 crew cab.
It seems as if my rear axel is locked in positive traction as if it had a solid rear axel. When I turn left the left rear tire will skid and the right one will when I turn right. It appears that both rear wheel are trying to rotate at the same speed.
I have not recently had the 4 WD engaged but I did cycle it through a few times trying to troubleshoot this problem.
Any Ideas would be appreciated.
I bought the truck 2 months ago so I don't have any mechanical history.
Thanks in advance.

 

Maybe it doesn't have the correct lube in it. With limited slip a friction modifier might be needed. I did have an older chev truck that did that and there was a broken piece inside the differential.

 

I have done a little more research and determined that it has the G-80 locking Diff. which does not require addative. I change out the lube using Lucas synthetic but still can not get it to un lock. I have tried doing the figure 8's forward and backwards but no luck.

 

Any luck with the rear end? I have the same rear end in my 98 C2500, ext cab. When I first purchased it, Used, it was low on fluid. Anyway long story since, I have replaced the axle seals and refilled. Make sure you use, the correct fluid with Limited slip.. Like I did. Also while the cover is off, spin the wheels over by hand and look at the gears,spiders, and clutch packs... they might be stuck or worn out... going on 2+ years and working great... good luck