If you are good (masochist), the rear cover can be removed and reinstalled without removing the output shaft nut. It requires a bunch of tranny shafts to come out with the cover. Me I had a tool made from a 27mm socket. Had the ratchet end cut off (so it was the 27mm hex all the way through. Then had a handle welded on. That way I can hold the output shaft with the forward yoke from an old dead u-joint, and loosen the nut (after bending back the bendy tab). Watch the speedo drive ball bearing and 2 hardened washers that sandwich the small (output) speedo drive gear.