Kyosho UM788 Rear Upper Bulkhead Ultima RT6

This is the rear upper bulkhead for the Kyosho Ultima RT6 stadium truck.

The upper bulkhead is the top half of the rear gearbox housing. It closes over the differential and the transmission gears, carries the upper bearing seats, and provides mounting points for the rear camber links and shock tower. That makes it a structural part rather than a cover: its fit determines whether the diff and idler gears stay in alignment under load, and a cracked or distorted bulkhead lets the gear mesh wander, which chews through gears and bearings quickly.

It is a common casualty in heavy rear-end impacts and in landings that come down hard on the rear tower.

This is the genuine Kyosho replacement, molded to the original dimensions so it mates correctly with the lower bulkhead, and your existing bearings, gears and hardware go back in without shimming. Fitting it restores the factory gear mesh and rear geometry rather than approximating it. Kyosho lists this part specifically for the Ultima RT6; the corresponding RB6 buggy part is a separate number.