The Eaton Posi 19559-010 is a clutch-type limited-slip differential for the GM 8.5 inch and 8.6 inch 10-bolt axle with 30-spline axle shafts. It uses race-bred carbon friction discs in a fully rebuildable housing, and the clutch preload is tunable by swapping spring packs, so the traction bias can be dialed in for the application.
- Type: Clutch-type limited-slip differential (Eaton Posi)
- Axle: GM 8.5in / 8.6in 10-bolt
- Ring gear diameter: 8.5 in / 8.6 in
- Axle shaft diameter: 1.32 in
- Spline count: 30
- Gear ratio: 2.73 and numerically higher
- Rebuildable: yes, tunable clutch preload
- Part number: 19559-010
Axle Fitment
- Fits the GM 8.5in/8.6in 10-bolt axle (30-spline, 2.73 and up), front or rear, used across many GM cars and trucks. Confirm your axle and spline count.
FAQ
What axle does the 19559-010 fit?
The GM 8.5in and 8.6in 10-bolt axle with 30-spline shafts.
Is it rebuildable?
Yes. The Posi uses replaceable carbon friction discs and a rebuildable housing, with preload tunable by spring packs.
What ratios does it cover?
The 2.73 and numerically higher ratio range for this axle.
How do I confirm fitment?
Confirm you have a GM 8.5in or 8.6in 10-bolt axle with 30-spline shafts before ordering.

