Working on my 66 MK1A, which has not been driven for decades, I noticed that the axles turn without moving the driveshaft mount. Then they engaged slightly, but with a tremendous amount of slip. I seem to remember that they locked up and had no slip. I recently had the rear end serviced and I am wondering if it has not been serviced correctly. Decades ago I would be on top of this but it has been so long since I worked on anything. Is all this slip normal or is it broken?