Evan

i bought a HPI racing spur gear 58t ball differential set for my micro but it does not match the old on that i stripped

Evan

i put it on and all it did was spin the spur gear and not the wheels or axles when i reved the motor

caveman

Have you built it following the instruction, you must tighten the wheel nut(right side) ,otherwise ,it will slip. Spur gear spins but no drive.

dux

Yeah, it's probably just loose. Also, get a Losi thrust bearing to fit in the hub where that plastic bushing usually is on the right side (in the wheel).