My 1967 MGB's rear end (tube style)has a clunk and a whine which changes with deceleration. With the car on a lift, today I was shown by a mechanic that there is play in the driveshaft before it turns the axle. This is not coming from the U joints but from the rear end itself. He recommended replacing the thrust washers (a 4 hour job) and possibly rebuilding the entire rear end (a job apparently not to be taken lightly).

Are there any sources for new or rebuilt MGB differentials?