Super Select
Super Select is the brand name of a four-wheel drive system produced by Mitsubishi Motors, used worldwide except for North America, where it was initially known as Active-Trac.
Power is sent to the front and rear axles with the centre differential locked, ensuring that a percentage of power is still sent to the forward axles even if a rear wheel is spinning (and vice versa) however the gearing ratio is doubled, increasing torque by more than 2x and reducing speed in each of the gears by the same factor.
In fact Mitsubishi recommends this mode for almost all situations due to the enhanced handling and safety and lower drivetrain strain when towing.
Unlike many part-time 4WD systems, 4H can be used on tarmac and hard surfaces without the risk of damaging the transfer case through gearbox windup (excessive, uneven torque applied to the transfer input/output shafts through the difference in rotation speeds of each wheel when on a high-grip surface that cannot relieve this through slippage on the terrain itself).
In order to shift into 4LLc, the operator pushes directly downward on the lever to bypass the lockout and forward into the 4LLc position.
Due to the combination of dog clutches and vacuum actuation, internal friction/tension can cause slow engagement at the diff when shifting at a standstill (as must be done when entering or exiting low-range) while shifting-on-the-fly is usually instant.
This results in a much stronger hub/axle assembly and greater reliability however means that the left hand side axle is always driven.
The small loss in fuel economy when in 2WD due to spinning the left axle is considered negligible and outweighed by the strength and convenience advantages.
[2] It is a full-time four-wheel drive mode using a viscous coupling unit (VCU) and center differential to direct drive to the front wheels when the rear axle loses traction, and is capable of handling a wide variety of road conditions and speeds.
Changing between 4HLc and 4LLc is only possible with the vehicle stationary (Note: 4HLc and 4LLc are your more traditional four-wheel drive modes, and should never be used on high traction road surfaces, as drivetrain 'binding' damage will occur).
For this reason, unless an additional selectable front locker is fitted, MATT is preferred due to its high performance and action on all four wheels.
As MATT uses the ABS system to rapidly apply and reapply braking force, in extremely slippery surfaces or when the wrong mode is selected (e.g. high range when it should be low range, resulting in excessive wheel speed and slip) the system's constant and rapid brake application on a constantly slipping wheel over an extended period of time (>1min continuously) can result in a short, temporarily low brake vacuum level.
In the event of a vacuum solenoid failure, the vehicle will remain in the axle configuration last selected (2WD or 4WD) and the centre diff light will flash continuously indicating a fault.
For this reason, if travelling into a remote location, it is advisable to use at least 4H so that in the rare event of a solenoid failure on the track, all the core 4WD modes of 4H, 4HLc and 4LLc will still be selectable as high and low ranges and the centre differential are manually selected via linkage and not dependent on electronics (with the exception of the most modern rotary dial models).
