Available in the Liberty (but you can find it in a junkyard near you under many Cherokees and Grand Cherokees), this system allows the largest selection of ranges out of all the Jeep systems. With two-wheel drive, part-time four-wheel drive, full-time four-wheel drive, and low-range four-wheel drive, this system is ideal for regions that see snow, slush, and sleet as a normal part of the winter.
In two-wheel drive, it sends power to the rear wheels and can be used wherever you want. In part-time four-wheel drive, there are all kinds of cautions about only using the vehicle in low-traction conditions because the center differential mechanically locks up. And in low-range four-wheel drive, the transfer case multiplies torque by 2.72:1 and allows for more control over technical stuff. In general, it behaves just like the Wrangler's Command-Trac.
It comes with the independently suspended Dana 30 front axle and the Corporate 8.25 rear that all Libertys come equipped with.
The really nice thing here is that between the part-time four-wheel drive and the low-range four-wheel drive, there is another option: full-time four-wheel drive. This splits the power 48 percent to the front axle, and 52 percent to the rear axle and can be left in this setting for any road condition - from dry pavement to black ice. That means if you are heading out and there is sleet coming down, you can put it in the full-time range and forget about it. It'll greatly improve your control in the messy stuff without having to constantly worry about damaging it if you hit a dry spot of pavement. The full-time selection is also a blast for fire-road blasting. Talk about sticking to corners!
If you want a Jeep-branded Subaru (or insert choice of all-wheel drive wagon here), look no further than the Quadra-Trac I with the NV140 "transfer case." Available in the Commander and Grand Cherokee, Jeep touts no levers or buttons needed "To enjoy the benefits of continuous four-wheel drive." We simply give a good laugh at both the sell-out Trail Rated badge and the Jeep emblem on a vehicle that is basically no better than an all-wheel drive wagon.
With no fuel-saving, two-wheel drive range, all while offering no real four-wheel drive (with a 50/50 front to rear power split) and no four-wheel low-range whatsoever, this system is a joke. Run from it. Shun it. Make fun of those who buy it. Charge people who get stuck and need a tug if they have this pansy "four-wheel drive" system. OK, you get the point ... moving along.
Like the Quadra Trac I system, the Quadra-Trac II is available in the Grand Cherokee and Commander, but that's where the similarities end.
This system comes with the NV245 active transfer case, which allows full-time four-wheel drive and low-range four-wheel drive. It also does some fancy electrical dance that we don't really get. However, we'll explain it like our 120-page encyclopedia explained it to us.
Under normal driving conditions, this space-age transfer case sends 48 percent of the power to the front wheels, and 52 percent to the rear wheels. However, using some whiz-bang computer processing (electronically controlled clutch pack in the transfer case and brake traction control system), it is able to determine which axle has the better traction and can seamlessly transfer up to 100 percent of the power to either end.
In low range, it behaves just as the rest of the non-Rubicon Jeeps - a 2.72 reduction sends the power out to either end. This is a mechanical coupling, and it always sends 50 percent to both axles.
Also included is the independent front 7.875 (7 7/8 inch ring gear) Corporate Axle with an 8.25 Corporate axle in the rear. We are really anxious to see the miniature front ring gear take that 100 percent of the engine's power.
It is easy to confuse the Quadra-Drive II with the Quadra-Trac II. They are both available in the Commander and Grand Cherokee; both systems come with the independent front 7.875 axle and solid 8.25 Corporate Axle. Both systems are full-time four-wheel drive based around the super whiz-bang NV245 transfer case.
The big difference is the Quadra-Drive II features front and rear Electronic Limited Slip Differentials (ELSD). The electronic differential immediately detects tire slip and smoothly transfers engine torque to the tires with the most traction. In some cases, Jeep claims, the vehicle will anticipate low-traction conditions and preemptively eliminate tire slippage.
Now if you were paying attention, that means that the transfer case is constantly varying output between the front and rear axles while the differentials in the front and rear axles are constantly varying torque transfer left and right. It does this all the time, however many thousands times a minute, actively channeling power to where it's needed. We'd like to take one out in a massive rock course with at least two wheels off the ground or mud pit and play with it until the dashboard reads "ERROR ERROR ERROR," 'cause that's a lot of electrical wizardry goin' on.