Well I've had this problem ongoing for awhile now and its recently gotten much worse. Basicly, with both wheels on the ground I can hand turn the driveshaft over half a turn in each direction before it locks. During driving this causes a smack that can be felt all along the drivetrain when on and off the throttle. Parts that have been replaced so far are a new center bearing, helical differential, and a new SR tranny. Yet with these the problem is still prevelant and is getter worse as time goes on. I am wondering if anyone has had this problem and what course of action did they use to repair and trobbleshoot the problem.