Chevrolet Repair: Limited Slip not Slipping, tight circles, rear diff

Question
Van, got a 95 K1500 Z71, 150,000mi.  Twice recently when I back up, then pull forward out of my parking space after the truck has sat a couple of hours I noticed the rear end is locked.  When I pull forward while turning the rear end hops and churps.  I can rock back and forth and it goes back to normal.  I just changed the fluid in the front and rear diff about 6mo ago.  Currently it's not leaking and it's full to the bottem of the fill hole.  In doing some research I have seen something called limited slip lube that should be added like a supplement to the differentials.  Could this be the problem or do I need to have the rear end rebuilt?  Thanks in advance...Colt

Answer
Hello Colter,
Do the sliplube first.Drain a little fluid out, and add the addative. Then go to a parking lot, and drive in some tight circles. Don't cut donuts, you don't want to spin the tires. You want to make the diff slip, so do it rather slowly.
There will be some noise, but it should quit as you force the lube into the needed places.
Do it in both directions, left and right.
A little reverse would probably help also.
I doubt you will ever need to overhaul it.
Van