Jeep WJ Grand Cherokee Quadra-Trac II to Select-Trac SwapPosted in How To: Transmission Drivetrain on October 1, 2011
It’s no secret that ’99-’04 4.7L V-8 WJ 4x4 Grand Cherokees equipped with the Quadra-Trac II package in either Limited or Laredo trim are pretty darn capable off-road, especially when compared to today’s IFS-toting car-like SUVs. This Jeep generally rolled off the assembly line with a NV247J transfer case when sporting the V-8, although we have heard rumor of both Limited and Laredo WJs with the NV242J transfer case. The truth is that the NV247J works pretty well both on- and off-road when everything is functioning, but as a transfer case the NV247J is very limited in its options. It allows high-range, 1:1 full-time 4-Hi (that supposedly will lock the front and rear axles if there is a great difference in front to rear axle speed), Neutral, and a 2.72:1 4-Lo (with the center viscous coupling locked). That’s it! This means that we were never sure if our Jeep was actually using four-wheel-drive when off-road in high-range. While on-road, the front axle was always being turned by the motor, even on dry pavement. Now since we, like many Jeep owners, are not very good at leaving well enough alone we decided to look into swapping in a transfer case that would allow us more options. The NV231J is a great choice. It allows 2WD, 4WD part-time with a 1:1 ratio and 4WD part-time with a 2.72:1 ratio. Also the NV231J HD can be swapped into a V-8 WJ (see “Part Time Grand,” Feb. ’09) and yet it still leaves something to be desired. What is that you ask? Well we use our WJ to flat-tow our ’49 CJ-3A and it seems that having full-time 4WD would be beneficial if we were ever to have to tow in ice or snow (like on the way to Moab). The solution? How about finding a NV242J to swap in? This transfer case, which was available from the factory in a WJ with the V-8 (although rare) and more commonly behind the 4.0L I-6, allows 2WD, 4WD part-time, full-time 4WD with a center differential, and 4WD low with a 2.72:1 ratio. That’s what we wanted and it was an easier swap than we expected! We were even able to use our stock driveshafts and we picked up 1-2 mpg as well.