Eaton Detroit Truetrac limited-slip differential.
The Ford 9” 35-spline Truetrac utilizes a 5 pinion set unit (10 pinions total) (most are 3 pinion sets). This differential is also strengthened and lightened. The Ford 9” 35-spline is the hot combo for most higher horsepower builds. The Truetrac operates as a standard (open) differential under normal driving conditions, allowing for unobtrusive operation. When a wheel encounters a loss of traction or the terrain changes, the helical-shaped gears mesh with increasing force, transferring torque to the high traction wheel until wheel spin is slowed or completely stopped. When the vehicle exits the low traction situation, the differential seamlessly resumes normal operation.