Two 4-syncro MGB gearboxes were opened for inspection, one in dire need of a layshaft and a good cleaning, the other in very good condition. The good one will be reassembled with new gaskets and seals and fresh oil, ready for the street car or a backup gearbox. The other will get a new layshaft and needle bearings, buff the carbon off of the syncro cones, thorough cleaning, and then reassembly.

The late model steel syncro rings are quite robust and long lived, as long as you keep the oil clean. Aging oil can carbon up the syncro cones and cause the syncros to stick, in which case it won’t go into gear.