Jeep 4WD Systems and How They Evolved

Jeep 4WD Systems and How They Evolved
08 Jun 2016

It’s four decades ago. You are driving your Jeep CJ-5 and you are ready to go off-roading. First thing you needed to do is engage the vehicle’s four-wheel drive.  The procedure is such: first you have to climb outside and twist hard-to-turn locking hubs on the right and left wheels. Then, hop back inside the CJ-5 and pull the large floor-mounted 4WD lever back.

Now time travel 40 years forward and you are sitting in the Jeep Wrangler Rubicon.  Let’s take a peek at some of today’s technology that makes you ready to go four-wheeling:

Intelligent traction

Nowadays, Jeeps tie the ABS brake system and traction control system together. These advanced systems can change the throttle action, suspension systems, transmission shift points, and even the differential locking operation.  This allows the vehicle to cater responses to specific off- or on-road conditions. For instance, the traction control allows slippage in “mud” modes, when more wheel spin is needed to keep you moving forward. But in “rock” mode, the vehicle may relax throttle responsiveness for steady and slow crawling.

Differential Locking

Standard differentials are made to allow for the right and left wheels on an axle to turn at different speeds during cornering.  The issue is that on a slippery surface, a standard differential sends much of its power to the wheel that turns with the least resistance.  Anybody who has driven in snow knows exactly what this is like; when somebody is on an icy road or a muddy trail, one wheel spins and the vehicle won’t move. The solution to this is a locking differential.  As long as your wheels are traveling straight, a “locker” will split power equally between right and left. Jeeps now have convenient push button locking differentials.

Suspension Adjustability

Suspension units for 4WD vehicles used to be a compromise between off-road and street traits.  The problem is that the long-travel springs, shocks, and swaybars made for off-roading would handle horribly on the street.  Today, the Jeep Wrangler Rubicon has not just used selectable locking differentials but also an electronically disconnecting front swaybar as well.  With an electronically disconnecting swaybar, a single press of the dash-mounted button will unleash tons of front wheel articulation. Similarly, adjustable air suspension allows for better performance on the street and also off-road. It allows the vehicle to ride at a lowered height on the road and then raise up the whole body to provide off-road trail clearance.

4WD

Thanks to electronics, nobody has to jump outside and lock hubs anymore.  There aren’t any annoying 4WD shifter levers either.  Now shifting is all done by the press of a button and you can do this while your vehicle is moving. This has made the process of switching from two- to four-wheel drive a simple affair. However, the serious leap came when modern electronics began managing wheel traction!

Final Remarks

As you have picked up on, the technology in 4WD vehicles has changed a great deal. Thank you to the sales staff at Reedman Toll in Langhorne, PA, a Chrysler, Dodge, Jeep, RAM dealer for explaining to us that the procedure to put a Jeep into 4WD is a little easier now.

Image by Wikimedia Commons

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Derek Sloan

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