THE H2 4WD SYSTEM
So there you are, heading down the trail for the first time and you have all these mysterious buttons in front of you to control your 4WD system, which ones do you need to push?
First and foremost, we should not forget one of the old off road clichés, "Drive as slow as possible, but as fast as necessary". There are times, sand, mud, etc, when you need to keep up a certain momentum to keep you going, however, it is generally accepted practice to tackle a trail as slow as possible. This not only allows you to see what is coming, pick the right line, and adapt to changing conditions, but it will also minimize the possibility of breaking something. So with that mind, unless absolutely required, a gentle and steady foot on the gas is needed at all times.
So what do the buttons do and which one should you use? As with all things, experience will teach you what settings are appropriate for the terrain you are tackling, but are some basic pointers we can use.
Traction Control System
Low Gear Selection
Transfer Case Use
4HI Lock or 4LO Lock
Rear Axle Lock
If the terrain is very uneven where you are may be lifting a rear wheel off the ground, then you may want to lock the rear axle. Likewise, locking the rear axle when tackling steep obstacles, uneven inclines, very loose sand and deep mud, will reduce the potential for getting stuck and keep both rear wheels moving. If you spin the wheels a lot with the rear axle locked, you may notice that the axle unlocks itself, this is to protect the axle and quite normal.
It is worth mentioning again, that when axles and diffs are locked, the potential for damage increases with speed or heavy throtle use. Drive slowly, and let the torque of the H2 work for you. You will see people deliberately spinning wheels on rocks and other terrain, sometimes to dry the tires out, other times to manhandle their way over a particularly difficult obstacle. This should only be attempted, if a/ you know what you are doing, and b/ you understand the potential risks involved.
Brake Throttle Modulation
Picture this, you are crossing a large log, at an angle so that one wheel at time goes over the log, as each wheel comes down the log gravity will take over and want to pull the vehicle down and forward suddenly. By using BTM you will prevent this from happening and make slow steady progress over the log. The same principles apply when tackling uneven rocky terrain, deep ditches, walls, sheer drops, etc.
Another application of BTM is when on a slippy or loose surface where momentum cannot be maintained, either due to potential hazards or a slow entry point. By applying BTM techniques you are partially recreating the same result as using a locker. The wheels with less traction are less likely to spin, as the brakes are holding them, allowing power to still be applied to the other wheels with traction. Good results can also be achieved using BTM when you have one of your front wheels in the air, BTM will allow some power to still be transmitted to the wheel on the ground. Obviously, special attention should be made not to suddenly release the brake when using BTM.
Another added benefit of BTM is that it deactivates TCS/TC2.
Ride Height Control
Although it's been said more than once, it is worth repeating one more time, "Drive as slow as possible, but as fast as necessary".
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Note: The information on this page is offered for guidance purposes only and is not a recommendation that anyone perform any task described. Consult a qualified technician before performing any work on your vehicle. Any task performed based upon this information is at your own risk. The Hummer X Club, it's members and affiliates, this web site, the creators, owners, contributors to this web site, advertisers or sponsors of events, and any other individual or organization involved with the information provided do not take any responsibility whatsoever for any damage, either directly or indirectly, that may occur based on the information provided. You perform any task described on this web site at your own risk and assume responsibility for your own actions.
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