How jeep® 4x4 systems work

[shobans]

Jeep® Compass models with a 5-speed manual transaxle or continuously variable transmission feature selectable four-wheel-drive lock. This state-of-the-art electronic system anticipates the need for added traction and responds to wheel-slippage by transferring power to the rear wheels, while modulating rear-wheels to contribute to vehicle stability in cornering situations. The system also saves fuel by operating only on demand when on-road, thereby minimizing power-robbing friction and inertia. Activate the off-road mode by pulling up on the chrome T-handle switch labeled 4WD LOCK in the center console. This mode dictates that the electronic system sends the maximum amount of torque to the rear axle for improved traction.

 

[jack2009]

Depends on which 4x4 system you have. Some are part time some are full time, and some are a combination of the 2.

First lets start with the part time system. This system should only be used in low traction conditions such as off road, or in snow, mud, sand, etc, where the vehicle in 2WD mode cannot keep a steady forward momentum you should engage 4WD Hi range. This allows full speed capabilities with all 4 wheels being able to move the vehicle. In extreme cases you can engage 4WD Lo range if the vehicle is mired in deep mud, snow, sand, or for higher torque needed when trying to pull a heavy load. Most times there is also a neutral position which is used to tow the vehicle on all 4 wheels.

The full time 4WD system allows the vehicle to be in 4WD all the time with a 40/60 torque split normally. When a difference in traction is detected by the center differential power is transferred to the axle with the most traction automatically. This type of system is engaged all the time and requires no input from the driver. Some systems include a low range 4x4 mode for the same use as mentioned under the part-time 4wd system. Also there is probably a neutral position in this system also.

The combination (full/part time 4wd system) incorporates both systems into one transfer case. Allowing the driver to decide which position to drive the vehicle in. This is great for situations where you are driving in snow or ice but the road is not completely covered there may be dry spots or just places that are wet in which you would use full time 4wd high range that way you aren't shifting into and out of 4wd constantly. If conditions worsen you could shift into 4wd hi range part time and have the system "locked" into 4wd and all 4 wheels will continuously pull the vehicle forward. Along with both of those positions you still have a 4wd lo range position just as mentioned above, and also you still have the neutral position. This type of system I think is by far the greatest idea as it gives the driver the option of full time or part time usage. Also with this system you can leave it in full time 4wd high range year round if you wish.

A note of advice for engaging 4WD lo range with any of the above systems, you have to have the vehicle rolling 2-3mph, shift the transmission into neutral, and move the transfer case shift lever through all positions and into 4lo. Being completely stopped will cause the system to not fully engage or not engage at all.

As for a 4WD system as in a wrangler, the 4WD systems are basically the same, or offered in both types of vehicles. The wrangler's 4WD systems are just geared lower in 4wd lo range for extreme off road usage.