First 4-Wheel Drive

[Big Z]

Here is the write up.

The sophisticated four-wheel-drive system and transfer case are versatile and driver-selectable. The integrated Borg-Warner two-speed electrically controlled full-time 4WD system is capable of further reducing the vehicle's gear ratios by 2.64:1 when necessary, for highly controlled obstacle climbing. It provides a 40/60 percent front-to-rear torque split in "High Open" mode or when the differentials are unlocked and a 50/50 percent front-to-rear power split when the transfer case differential is locked. A specially designed low-range throttle progression allows the driver to precisely control engine speed (and as a result, the vehicle) during very rough terrain driving, and is automatically engaged when the transfer case is in "4 LO."

The transfer case controls provide five mode selections, four of which can be accessed by dash-mounted button selectors. The fifth mode, neutral, is available by simultaneously pressing two of the button selectors. Selections include:

1) A high-range open or "4 HI Open" for normal, everyday driving on dry road surfaces at any speeds.

2) A high-range lock or "4 HI Locked" for semi-slippery surfaces like snow, light sand or wet areas, such as those around a boat launch; this selection locks the front and rear output shafts together, so their wheels rotate at exactly the same speed.

3) A low-range lock or "4 LO Locked" for severe off-pavement use, such as crawling over large rocks or logs. In addition to locking the two propshafts together, it provides a 2.64:1 gear reduction in the planetary gearset. By lowering the ratios of each of the gears, it adds the equivalent of another, extremely deep-ratio first gear and provides a great deal more torque for slow-speed climbing. Low Lock also activates a new, more measured throttle progression curve, which greatly enhances off-road driving comfort and control. High and Low Lock also allow a driver to select a different set of calibrations for the traction control system, using a separate "TC2" button. This provides additional wheel slip for select operating conditions and road surfaces, such as paddling through deep sand.

4) An Eaton electronic rear differential lock or "4 LO Locked + Rear Diff Locked," available only when the transfer case is in Low Lock position. It permits locking up the rear differential for optimum slow-speed capability in climbing over large rocks or up long, steep grades. It locks the two rear axle shafts together so they rotate at exactly the same speed-and does so electronically. (Since this mode can only be accessed when the transfer case is in Low Lock, the front and rear propshafts are already locked.)

5) "Neutral," obtained by simultaneously pressing the "4 LO Locked" and "4 HI Open" buttons and holding them down for 10 seconds. It permits flat-towing the H2 behind another vehicle