PCT No. PCT/US79/00597 Sec. 371 Date Aug. 13, 1979 Sec. 102(e) Date Aug. 13, 1979 PCT Filed Aug. 13, 1979 PCT Pub. No. WO81/00384 PCT Pub. Date Feb. 19, 1981
A hydraulic fluid brake system having a differential lock causes all of the torque from the engine to be delivered to the non-spinning wheel resulting in overloading of the components. By providing a non-locking differential (54) and a hydraulic fluid brake system (10), a controlled braking of the spinning wheel will provide a torque to the non-spinning wheel substantially equal to the torque from the braking of the spinning wheel and not allow the spinning wheel to be fully braked. The operator can selectively move a valve member (26) and maintain a modulated source of pressure (20) to the non-spinning wheel and controllably modulate the fluid pressure at the spinning wheel, thus controlling the braking effect of the brake on the spinning wheel. This arrangement controls the torque and eliminates harsh braking of an individual wheel.