The ARB Air Locker RD221 adds selectable locking to the common GM 8.5" 10-bolt axle (AAM 860, 28-spline). Lock it 100% at the flick of a dash switch for climbs, mud and rock, then release it to full open-differential behaviour so the vehicle drives and wears tyres just like stock.
Found under a wide range of GM trucks and SUVs, the 8.5" 10-bolt is a strong, popular platform for traction upgrades. ARB's forged four-pinion centre handles the extra load of larger tyres, and air-operated engagement delivers instant, repeatable locking in any gear.
Specifications
| Attribute | Detail |
|---|---|
| Differential / housing | GM 8.5" 10-bolt (AAM 860) |
| Spline count | 28 |
| Engagement | Air-operated, driver-selectable (100% locking) |
| Behaviour when off | Full open-differential operation |
| Brand / MPN | ARB / RD221 |
Fitment note: Air Lockers are selected by differential and spline count — confirm your GM 8.5" 10-bolt axle is 28-spline before ordering. Note: this item ships from stock and is not available for direct drop-ship.
Requires an ARB air source (on-board compressor or CKMA/CKMTA kit) and an installation kit. Backed by ARB's limited warranty.
Prop 65 WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or reproductive harm. See www.P65Warnings.ca.gov.
Browse more ARB traction & differentials.
Presented by Overland Kitted
The Dispatch
Gear We Like: DVA Mechanics for the Grenadier
MAXTRAX Introduces Universal Mounting Pins for MKII, XTREME, and LITE Boards
