Abstract: In a differential gear mechanism housed in a case and having a power input and having two output shafts extending outwardly through the case for delivering drive torque to the two output shafts, each of said shafts driven by a helical side gear, said side gears axially aligned in contiguous relationship so that the end thrust of both of them is additive toward one output shaft, and a friction-reducing washer is provided surrounding said one of said output shafts in position to take end thrust between the traction gear associated with said shaft and the case, whereby to substantially equalize the torque delivered to the two output shafts; or one or more friction-increasing washers are provided surrounding one of said two output shafts in position to take end thrust between the differential and the case, whereby to decrease the torque delivered to said shaft when necessary to provide a predetermined control of torque, as from a transfer case.