The Eaton Detroit Truetrac is a helical gear-driven limited-slip differential that puts down the traction available at each wheel while sharpening handling and drivability. It works smoothly and automatically with no maintenance, and suits nearly any street, tow, or trail vehicle that wants a quiet traction upgrade without the on and off behavior of a locker. This unit fits the GM 8.875in 12-bolt truck used in GM 1/2-ton trucks running the 8.875in 12-bolt truck rear axle.
- Type: Helical gear limited-slip (Detroit Truetrac)
- Axle: GM 8.875in 12-bolt truck
- Ring gear diameter: 8.875in
- Axle shaft diameter: 1.30in
- Spline count: 30
- Gear ratio: 3.73 & up
- Maintenance: None (fully automatic operation)
- Part number: 913A315
Axle Fitment
- Fits the GM 8.875in 12-bolt truck, 30-spline, 3.73 and up ratios, as used in GM 1/2-ton trucks running the 8.875in 12-bolt truck rear axle. Confirm your axle and spline count.
FAQ
What axle does the Eaton 913A315 Truetrac fit?
It is built for the GM 8.875in 12-bolt truck, 30-spline, 8.875in ring gear. Verify your axle and spline count before ordering.
Does the Detroit Truetrac need any maintenance?
No. The Truetrac is a fully automatic helical gear limited-slip that operates smoothly with no clutch packs to service and no maintenance.
Will it work with my gear ratio?
This unit covers 3.73 and up ratios. Match it to your ring and pinion setup when planning the build.
Is the Truetrac good for street, towing, and trail use?
Yes. It works automatically and quietly, so it suits street driving, towing, and light off-road use without the on and off behavior of a locker.
Does it come as a complete differential?
Yes. The 913A315 is a complete Truetrac differential unit. Setup uses standard install parts (bearings, shims, and seals) sized for your axle.
