DISTRIBUTION AR 3808806 - Caterpillar

Traction Systems
For the majority of applications, a conventional differential functions best. However, when a truck encounters a slippery surface a conventional differential will permit one tire to lose traction and spin. A characteristic of conventional differentials is equal torque to both axles. Therefore, the rear tire that has good traction receives only as much driving torque as the spinning wheel can generate (usually not enough to move the truck). The NoSPIN differential will keep both driving axles locked together in this situation, so all torque goes to the tire with good traction.
Manual anti-spin schematic.
In extreme hauling situations, where traction is very marginal, the Detroit NoSPIN is the most effective traction differential. As traction conditions improve, however, the NoSPIN may direct all driving torque to either axle. This can increase tire wear, stress axle and final drive components to the point of failure and reduce steering maneuverability.
The Caterpillar anti-spin system, enables the operator to brake the spinning axle (wheel) which increases the amount of torque necessary to turn it. This causes more torque to be directed to the wheel that has good traction, increasing the tractive effort. It is used with a standard differential. Operation in dry road conditions are not affected by the control.
Some advantages of the manual anti-spin over the Detroit NoSPIN.
1. Improved tire life in dry conditions when compared to the NoSPIN.2. Normal steering maneuverability.3. Decreased stress loads on drive train.Operations
The manual anti-spin is an air/hydraulic system consisting of a control lever, three valves and connecting hoses. See the illustration. The control lever is located on the steering column below and to the front of the retarder lever. When applied, this lever actuates an air valve (B) that sends a signal to a three-position hydraulic switching valve (A). This valve controls the oil supply which keeps the spring actuated parking/secondary brake disengaged.
When activated, the valve reduces the oil pressure to 1520 140 kPa (220 20 psi) to the spring applied brake so there is partial braking of either the right or left wheel. During actuation, oil at 3720 kPa (540 psi) minimum pressure is supplied from brake modulation valve (C), through switching valve (A), to the brake that is to be kept released. At the same time, oil, to the brake that is to be applied, is directed through switching valve (A) to the relief valve (D). The oil pressure, to the brake that is to be applied, is lowered to 1520 140 kPa (220 20 psi) and the spring force in the parking/secondary brake partially applies the brake. Oil which crosses over to relief valve (D) returns to the hydraulic tank. When the lever is released, switching valve (A) returns to the neutral position by spring force.
Troubleshooting The System
For troubleshooting, pressure gauges should be installed at each rear brake in the release supply line for the parking/secondary brake. With control valve (B) in the neutral position, a minimum of 3720 kPa (540 psi) should be indicated on each gauge. The maximum