Kyosho UM612 Diff Shaft Ultima SC (2)

Kyosho UM612 is a genuine pair of differential shafts, also known as outdrive joint cups, for the sealed gear differential on Kyosho's 1/10 off-road vehicles. These steel cups bolt into each side of the diff and are the connection point between the differential and the driveshafts: the drive pins ride inside the cups and transfer all the power from the diff out to the wheels. Because every bit of torque passes through them, the cups gradually wear grooves where the pins run, and worn outdrives create driveline slop and can eventually let a driveshaft pop out under load.

These install as direct replacements in the Ultima gear diff, with fitment covering the Ultima SC, RT6, DB, and RB6 vehicles that use this differential design. Swapping in a fresh pair during a diff rebuild tightens up the whole driveline and restores crisp throttle response. Package includes two diff shafts, one for each side of the differential.