210 diff problem?
 

im in the middle of building the diff. followed the usual instructions etc but i find the diff halves are slopping side to side a little , the diff screw is tight, got the correct shim in it etc and ive took it apart and re-checked everything but still the same.?

I'm not sure if this will solve your problem, but its worth checking.
The internal diameter of the two thrust race washers are different - one is slightly smaller. You can see this with your eye - you don't need a calipers.
Make sure the smaller ID washer is closest to the diff bolt head.

make sure and watch the diff build video on the Durango website
it explains a whole hell of a lot more than the rubbish manual

will do mate, and cheers.