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Progressive Torque differential

The Progressive Torque limited-slip differential (PTD) is Eaton's next generation of torque control technology, providing improved traction in the most challenging terrain. This heavy duty solution features unique precision forged gears with a three-pitch design, giving the unit increased strength and capability over standard single-pitch bevel gear products.

Equipment operators will experience an immediate response to changing surface conditions as the exclusive gear design and unbalanced gear meshing will provide a torque bias of up to 3.5:1. Additionally, the PTD is suitable for both original equipment or replacement applications and is engineered to work effectively in front-axle, rear-axle and inter-axle applications.

Long Life
No wearable parts
Immediate response
Small to large industrial applications


  • Powers both drive wheels, yet permits differential action to compensate for wheel speed differences. 
  • Uses unbalanced gear meshing to reach a torque bias of 3.5:1
  • Syncronized gear arrangement of the profiles creates the “progressive” torque biasing operation.
  • Under normal road conditions, the PTD performs like an open differential. On wet, muddy, icy or loose terrain, torque is transferred to the wheel with the highest traction.


The Progressive Torque Differential (PTD) is a torque sensitive "progressive" limited slip differential. It powers both drive wheels, yet permits differential action to compensate for wheel speed differences. The PTD is made up of two side gears and four pinion gears (units with two pinions are also available). A series of unique gear teeth are repeated about the gear face, each defining a different line of action and torque lever position. The unique tooth profiles of the side gear and pinion gear can only mate together in a specific way. This synchronized arrangement of the profiles creates the "progressive" torque biasing operation of the PTD. When traction is needed the pinions begin to rotate. The amount of rotation is the deviation angle, which progressively increases the torque biasing action through the gear set. The torque bias increases until the required bias is delivered up to 3.5:1 bias ratio.