[ss6]

You can check the right angle drive on the tranny by removing the cable, jacking the rear wheels, and rotating them. The slot thingy in the drive should rotate with the wheels, tho not necessarily at the same ratio.

If you have a helper, disconnect the cable at the speedo and at the tranny, then try to rotate one end of the cable and have your helper hold the other end still. If you can rotate your end in either direction, you need a new cable.

If both of these tests "pass", then the speedo itself is toast.