Diff probs

Hey just wondering if anyone had struck the problem of shuddering at low speeds when turning hard lock.....? I've been told by my mechanic that it is my differential and will cost in excess of $NZ1000 to fix. Seems a bit off to me? Any ideas?

Thoughts
Cheers
SXY

It does sound like a diff problem. 4WD vehicles do the same thing because the tires are all locked together thus have to move the same speed (when turning the outside wheel has to move faster because of the bigger turning radius, so the only way it can is by dragging/skipping).

Im not sure about the price though, Id ask around and get more opinions.