Command-Trac 4 wheel drive usage?

Question

My husband has a Grand Cherokee with command-trac drive train, consisting of 2 wheel H/ 4 H part time/ 4 L part time. In what situations should he use the 4 wheel drive side - and for how long without damaging the transfer box? The owners manual is in italian! Many thanks for all help as cant find anything specific on the internet.

Answer 1

Any part time 4wd system should only be used when operating conditions such as snow or ice are present or in offroad situations which allow the wheels to slip or spin. If a part time 4wd system is used on dry pavement you will wind up the transfer case (torque) due to the wheels not being able to slip and release excess torque. Which leads to drivetrain failures which are very expensive to repair. 4WD low range should only be used offroad and when extra pulling power is needed such as to extract a vehicle that is stuck, or to help extract the jeep in your case if it becomes stuck. Neutral can be used to tow the jeep on all 4 wheels such as behind a motorhome. Normally the transfer case should be left in 2WD. With either 4WD mode you can use it as long as conditions allow. If the road dries off, then you should go back to 2WD mode. You can drive in 4WD high range at any speed that is safe to do so. Shifting into 4WD low range should be done with the vehicle rolling at 2-3mph or the gear train will not line up and won't engage. 4WD low range you should not exceed 35MPH (which is pushing it a bit far) and should also be disengaged when conditions no longer require extra pulling power. Also using low range and 1st gear offroad going down a steep hill will keep the vehicle going slowly down the hill without riding the brakes.



Jeeps are great vehicles, take care of it and it will last many years.



Hope this helps, if you have any further questions feel free to email me at [e-mail]

Answer 2

Both 4 wheel drives are for situations where you have poor traction - either snowy, icy, VERY wet roads or off-road situations.



4 Lo is for when you need a lot of torque at low speed. This would be extremely steep hills, extremely rough off-road conditions - basically conditions where you're not going to go more than 20 mph anyway.



You don't want to use either 4-wheel system on dry pavement. In 4-wheel drive, both axles will spin at the same speed. Unfortunately, it's impossible to get two axles and four tires the exact same size. If there's a 100th of an inch difference, after a 1000 rpm, the larger tire/axle combination should have travelled an 1 1/2 inches further than the smaller tire/axle combination. Since both are attached to the same vehicle, it can't. That means one of your axles winds up like a spring until the tension can be released by forcing the tire to slip or by trashing the axle or transfer case.



In conditions where you know your tires are going to slip (which is why you put it into 4-wheel drive in the first place), there's no problem. On dry pavement, it's hard to make the tires slip, but they will eventually (hopefully), causing excessive tire wear. Do that enough and the accumulated stress on the axles and transfer case will cause them to fail sooner.



In other words, it's kind of like smoking. It's not a matter of smoke more than 2 packs today and you die. It's that each cigarette shortens your life expectancy by some small amount.

Answer 3

On mine there`s are sticker on the back of the drivers sun-shield that gives the info on where and when to use the various options.4 H and 4L part time drive are only to be used on loose or slippery conditions 2H is for "normal" conditions. Part of the problem is that there are many different transmissions fitted to the various models. Selec Trac is whats on mine and I keep it in 4Full time all the time, hardly ever use it in 2Full time. Evens out the tyre wear, and before some "expert" tells me, no, I don't get "transmission wind-up",thats what the centre diff is for !

Answer 4

This type of drive should only be used when on sand gravel mud ice or snow as the hubs are locked and if on dry surface will strain the transmission.

Answer 5

I used 4wheel part-time during the winter when it snows or gets icey, other then that I don't use it. I use 4wheel high when I need them all on now. Part-time and high can be used anytime and for as long as you like, low is for bad stuck situations.

Answer 6

2wh/4wh are prety safe to us e at any speed .but do not use 4wd low at more than 30 mph it will ruin your transfercase