The wife got her 2 wheel drive C1500 stuck yesterday so I am thinking about putting in a limited slip differential. Any tips on after market vs. junk yard parts and how well they perform?
Talk to your local dealer. Some times you can just buy the brand new limited slip that fits in that rear end for a couple hundred dollars. Its nothing special, we have put a couple of them in ourselves.
Limited slip with some decent all-terrains works out pretty good. Its amazing the difference. Even in the trucks that are 4x4, if they have limited slip front and back the open diff. trucks 4x4 can't compete.
You can likely buy something aftermarket for less than a limited slip diff from the dealer. ARB makes some good airlocking diffs. Just make sure when you do the install that you shim the diff correctly, otherwise you'll be looking to replace it in 10,000 miles or so.