ARB Air Locker RD127

£714.00 inc. vat

(£595.00 excl.vat )

RRP - £834.00 inc. vat - you save £120.00 inc. vat



Series 1, 2 & 3 - 1948 - 1985 (front & rear) 2,3
Defender 90 - 1984 - 1993 (front) 1
Defender 90 - 1983 - 1993 (rear) 1,2
Defender 110/130 - 1983 - 1993 (front) 1
Discovery 1 - up to 1993 (front & rear) 1
Range Rover Classic - up to 1992 (front & rear) 1,4

Fits 10 Spline vehicles

All ARB Air Lockers are manufactured in a world class, aerospace standard machine shop in Melbourne. Utilising aerospace grade materials and state of the art machinery, the facility ensures that the Air Locker maintains its reputation for quality, durability and reliability throughout the world. The ARB Air Locker is the only locking differential that offers an industry leading five year warranty and is available for an extensive range of vehicle models, with over 100 applications

ARB Air Lockers use a pneumatically controlled locking mechanism to switch between an open carrier and a fully locked differential. Once installed, all it takes is the simple flip of a switch to go from an open differential that works well on the street to a spool that provides 100% traction to both wheels off-road.


ARB lockers require no special tools or skills to install, apart from those necessary for fitting a standard differential. An ARB air compressor is the only additional thing you will need as each ARB locker comes complete with switches, solenoids, fittings, nylon air line, and even shims and bearings (if applicable).


ARB Air Lockers are sold in over 80 countries and there are over 150,000 units currently in use worldwide in both military and civilian applications. The secret to their success and reliability is that each ARB locker is designed and tested beyond the breaking point of standard and aftermarket axles such that your axles will break before causing any damage to the air locker.


  • 1 If vehicle was manufactured during 1993, check spline count.
  • 2 Air Locker not available for vehicles equipped with high load option.
  • 3 Ring gear spacer required. Longer ring gear bolts (not supplied) are also necessary - (Land Rover part no. 576521).
  • 4 When an DA4191 Air Locker is to be installed in Range Rovers manufactured prior to 1980 (approx.), special carrier bearings (No. K11300/K11162) may also be necessary - Land Rover part no. RTC3426.
  • 5 Some vehicles have crown wheel bolts which cannot be reused and must be replaced. Consult service manual.
  • 6 P38A is most commonly found in traction control equipped vehicles. Identify P38A type diff by large 205mm [8.07"] flange diameter. P38A was not used on North American delivered Discoverys - use DA4193.
  • Further Information:

    Shaft Description Rover type
    Shaft Diameter 28.2 (1.11")
    Splines 10
    Ratio 4.7


    Series II Discovery 1 Defender 90 Freelander 1 Range Rover Classic
    Series III Discovery 2 Defender 110 Freelander 2 Range Rover P38
    Discovery 3 Defender 130 Range Rover L322
    Discovery 4 2020 Defender 90 Range Rover Sport
    Discovery 5 2020 Defender 110 Range Rover Evoque
      Discovery Sport     Range Rover L405
    • Product Code:1201-FD
    • MPN:DA4191