Diff Slop
 

I can turn the rear wheels about 3 inches before the drive shaft moves. Is this normal or any suggestions as to what is wrong. I have a soft locker in an 8 inch third member.

Three inches at the circumference of the tire??? That's not too bad with a locker.

How much ring/pinion play at the driveshaft??

I had a limited slip in my old 85 rear end and it did about the same.....