Chevrolet Repair: Chevrolet differential, chevy dealer, rear differential

Question
I own a 1995 3/4 ton 4x4 extended cab Chevy and have had the truck since 1996.  I had the rear differential replaced at just under 50,000 miles and now it is going bad again.  This was done by an authorized Chevy dealer in Redmond, OR.  I don't abuse the p./u nor haul heavy loads with it.  I recently changed the oil and that is when the noise started.  There was no metal when I dropped the oil.  I pulled the wheels and found some end play on both sides.  Could you possibly help me out here?  I do not understand why this p/u has a rear end problem.  Or is it just a design flaw or something like that.

Answer
Hi Joe,
No regular problem with them...I have several at work.
There are a couple possibilities.
Occasionally, when the vehicles are loaded on transports at the factory, it seems there may be some competition concerning who can boom them down hardest.
I have needed to have axle tubes straightened up. Actually sat there with a "V" shape, although it was hard to see unless you were looking for a problem.
The other thought on the noise is, if you have a limited slip, be sure to use the correct oil, or it will make noise.
Good luck,
Van