Dual range gearboxes allow the driver to select between higher and lower range of gearing; introducing a new level of versatility when lower speeds would be more suitable to the terrain. The high range is generally used in normal driving conditions, and the low range is selected when the terrain requires higher torque at slow speeds.
The Subaru dual range gearbox is recognised as one of the most effective and versatile AWD transmissions in the automotive industry today. The hi/lo range setup allows for comfortable daily city driving with the option to easily adapt to more demanding off-road terrain.
Although Subaru’s symmetrical AWD system is outstanding in off-road conditions, the low range gear reduction drastically reduces gear speeds; implementing an effective engine brake down steep hills and making it easier to slowly navigate obstacles with more precision and control.
Although the dual range is widely available in many naturally aspirated 4-cylinder models, Subaru never optioned the dual range box to their turbo or H6 model Range. Considering the demand for an adaptable transmission to suit both on and off-road applications, ADS technicians have developed a conversion kit for all EJ turbo and EZ single-range models.
This isn’t an off the shelf kit removed from another vehicle; each dual range conversion is enhanced, revised and customised to allow for an effective synthesis of practicality, driveability and durability. By utilising a range of turbo and NA internals, along with our revised selectors and shifters, the ADS dual range conversion is guaranteed to help you navigate through the most demanding terrains with ease.
ADS Dual range transmissions can be assembled with the added strength of shot peening and ISF treatments. This is a vital step in the process when pursuing durability and strength dual range conversions for turbo models.
The Shot peening Process compresses the outermost layer of the treated component via high pressure metal sphere bombardment. This treatment introduces a strengthened outer layer which reduces the possibility of crack formation on a surface.
ISF is a polishing process which reduces friction whilst improving gear fatigue resistance. As friction is reduced, so is the operating temperature of the gearset.
Front and rear Cusco LSD units are also available for those pursuing ultimate off-road traction. These are available in a range of options and can be systematically adjusted to suit your specific off-road application.
Every individual gearbox component is laid out and inspected before assembly commences. The dual range transmission consists of an additional hi/lo gear cluster, so they can be quite complex when assembling.
Our transmission team consists of three specialist trained technicians, one of which has over 30 years experience in Subaru gearboxes.
Every transmission housing is Hydro blasted, hot tank cleaned and pressure washed in our 4000psi cleaner for a like-new appearance; we don’t paint our gearboxes.
Every gear set is assembled with all new components and lock nuts to strict ADS specifications. Tooth profiles and side clearances are all checked, amongst adjustments.
Front diff unit is assembled with the Cusco hemisphere and new genuine bearings. Subaru transmissions require Special Service Tools (SST) to correctly adjust the diff preload.
Input and output gearsets are installed; Meshing and backlash is checked and adjusted as required.
The dual range cluster is now installed with a final control check before sealing and closing the gearbox
If all checks are a pass, the housings are sealed, assembled and torqued to spec
Transfer case is assembled with an RS20kg centre diff unit. An upgraded 12/20kg centre diff increases driving response and durability, while traction on loose surfaces is significantly improved.
Transfer gear heights are measured for the correct shim clearances; once the correct shims have been installed, the transfer case is sealed, assembled and torqued to spec.
The transfer case is then installed to the gearbox housing.
The transmission is torque checked again, cleaned and bench tested. Once testing has been finalised, the transmission is ready for install!
The ADS All Terrain Dual Range is the next level up within our conversion range.
Our design and engineering team were given a very specific criteria during the development stage; build a transmission that will traverse most off road terrains, whilst maintaining on road practicality, driveability and comfort. Oh, and it needs to comfortably support modified turbo engine power outputs. Using a very unique combination of factory gearbox internals from a range of Australian and Overseas models, our techs have designed, tested and developed the most effective and robust dual range conversion available ANYWHERE.
Although we utilise the same super clean housings as all of our transmissions and same revised bearings and new genuine seal kit used in the assembly processes, that is pretty much where the similarities stop. The All Terrain 144 contains Subaru’s lowest hi/lo gear ratio of 1.447, a Shot Peened and ISF strengthened gearset, New genuine STI front LSD unit, and our ADS RS12 centre diff to compliment the setup. As is always the case, ADS gearbox technicians measure and assemble the transmission to our specifications and clearances to guarantee quiet, smooth and durable operation.
If you’re the type to seek out a barely recognisable track littered with the burnt out remains of the other off-roaders (Toyota’s, Nissan’s etc) that didn’t quite make it, then The Warrior 161 is the next (really) big upgrade you need.
Put simply, we have a saying at ADS: Nothing succeeds like excess.
The ADS Warrior Dual Range transmission will instantly turn your Subaru into a mudslinging, mountain climbing warrior. This unit offers the ultimate versatility and practicality for those who tend to choose a destination off the map and then make their own tracks there. Our design and engineering team weren't given a specific checklist or build criteria for the development of this transmission; they were unleashed with one simple instruction: Build something you’d install in your car. Using the same unique combination of factory gearbox internals found within the All Terrain, our techs decided to ISF and shot peen the front diff crown and pinion, as well as the hubs and sliders in addition to the gearset. The Warrior 161 is assembled with our very own Billet 1.61 crawler gear, a new Cusco RS 1-Way or 1.5Way front LSD unit, and our ADS RS20kg or RS40kg centre diff to perfect the setup.
As is always the case, ADS gearbox technicians measure and assemble the transmission to our specifications and clearances to guarantee quiet, smooth and durable operation.