Help, driveshaft runout

[steve j]

I`ve found out what the rumbling is under the S2, the left hand drive shaft has a bit of runout. The trailing arm actually drops by about 1/2 inch along with everything else attached to it, suspension etc. I can only think of two possible causes, bent driveshaft or diff problems. I can remove the driveshaft and run it on a flat surface to check it, if the driveshaft is ok, how do I check the diff? The right hand driveshaft is fine. Anyone had this before? All suggestions gratefully recieved, cheers. Forgot to mention, recently took off the cv joints to clean and grease them, is it possible that the joints could be off centre?
stevej

Edited by steve j on Monday 10th July 22:40