2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 275Get this manual
FINAL DRIVE FRONT GEARCASECENTRALIZED HILLIARD ADC
Operation
Engaging front gearcase: The AWD switch may be turned on or off while the vehicle is movingAWD will not enable until the engine rpm is below 3100 RPMOnce enabled, the AWD remains engaged while the front gearcase is moving and will not disengage until the rear wheels regain tractionEngage the AWD switch before getting into conditions where the front wheel drive may be neededIf the rear wheels are spinning, release the throttle before switching to AWDRing Gear Roller Cage
Rollers
CAUTION
Switching to AWD while the rear wheels are spinning may cause severe drive shaft and gearcase damageAlways switch to AWD while the rear wheels have traction or are at restWith the AWD switch off the vehicle drives only the rear wheels (2 wheel drive)When the AWD switch is activated it engages the hilliard, locking both front axles into all wheel drive when there is loss of rear wheel traction
CAUTION
If the rear wheels are spinning, release the throttle before turning the AWD switch onIf AWD is engaged while the wheels are spinning, severe drive shaft and clutch damage could resultDisengagement: As the front and rear wheels gain equal traction, rotating very close to the same speed, the transmission shaft "overdrives" the front gearcase inputThe rollers release outward, disengaging the AWDThe vehicle is now back to rear wheel drive until the next loss of rear wheel traction