Super T10 4-Speed Manual Transmission Synchro Set

This is the synchronizer service set for a Borg-Warner / Richmond Super T-10 four-speed, Richmond part number T10PRK. It is what you pull off the shelf when a Super T-10 has started grinding going into second or third, or when it kicks itself out of gear on decel and the gear teeth themselves still measure fine. Nine times out of ten the gears are usable and it is the brass and the shift keys that are worn out.

A Super T-10 synchro wears in a predictable way. The brass blocking ring cone glazes over and loses its bite on the gear cone, so the ring stops slowing the gear down before the sleeve tries to engage, and you get the classic 2-3 grind at anything above a slow shift. At the same time the three shift keys and their springs lose tension, the sleeve no longer gets held centered, and the box starts popping out of gear. Replacing rings without replacing the keys and springs is the single most common reason a fresh synchro job still grinds.

On the bench this goes in during a normal teardown. Split the case, pull the main shaft, and press the synchro hubs off. Before you assemble anything, set each new blocking ring squarely on its gear cone by hand and measure the gap between the ring face and the gear teeth with a feeler gauge - a new ring should sit well off the gear, and if it drops flush the gear cone is worn and the gear needs to be replaced too. Load the keys and springs into the hub with the spring tangs offset from each other so the sleeve is held evenly, then check that the sleeve slides across the ring smoothly with no notch.

Richmond builds the Super T-10 and its service parts, so this set matches the original geometry rather than a generic aftermarket approximation. It ships as a 6 lb boxed set from Richmond Gear under part number T10PRK.