be gradually angularly accelerated relative to the other shaft the housing 36 will frictionally brake the gears 16 and 18 against rotation relative to each other as the angular speed of the shaft 26 reaches a predetermined angular speed furthermore the torque transferring capacity of the instant invention also may be brought into play upon rapid acceleration of the shaft 26 as for example if the two drive wheels not shown of the associated vehicle mounted upon the remote ends of the axles 12 and 14 are disposed such that one is on a slippery surface and the other is on a surface offering at least reasonably good traction if the manual or automatic transmission not shown of the associated vehicle is quickily actuated to impart rotation to the pinion gear 24 the resultant rapid acceleration of the ring gear will cause the drive wheel having the least traction to initially spin thereby causing even faster acceleration of the differential gear 28 and the cam block 54 thereby causing the rollers 56 to cam the shoes 60 and 62 apart at their ends remote from the pivot connection 64 therebetween this of course will cause the housing 36 to be quickly cocked to the position thereof illustrated in fig3 and to frictionally engage and thus brake the.