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.
First you have to find a donor...
First you have to find a donor Jeep to pull the NV242J out of. We found a ’91 XJ with a recently rebuilt NV242J for $75 at a self-service junkyard. We are willing to bet that the best option would be to look for a wrecked V-8 Selec-Trac WJ, but they are rare. The next best option would be a similar year 4.0L 4WD WJ—then you could get the transfer case and the shifter-housing from the middle console to avoid having to modify the NV247J’s shift arm as mentioned below.
The hardest part of the swap...
The hardest part of the swap is removing a roll pin from one of the NV242Js shift forks. The XJ factory service manual says to use an easy-out to remove the pin, but we pried the main shaft past the shift fork and shift rod without removing the pin. We then removed the pin while it was out of the transfer case and reinstalled a new pin as per the re-build instructions once we had the input gear swapped into the NV242J.
Next you have to swap the...
Next you have to swap the input gear from your NV247J (left) into the NV242J. This is as easy as rebuilding the NV242J, which sounds complicated but is really rather easy with a good pair of snap ring pliers and a factory service manual. We’ve said it before and we’ll say it again, New Venture transfer cases are the Legos of the Jeep world. The V-8 input gear is basically the same as the 4.0L version, only longer.
The narrower bearing goes...
The narrower bearing goes with the longer input gear and is swapped from the NV247J T-case to the NV242J, along with the input gear.
Our shifter still says “4...
Our shifter still says “4 ALL TIME”, “N”, and “4 LO” and that’s OK. We know that when the shifter is all the way forward we’re in 2WD, the next notch back is part-time 4WD High-Range (with the center differential locked), the next notch is full-time 4WD High-Range with the center differential open for road driving, the next notch is Neutral, and the last notch or all the way back is 4WD Low-Range with the center differential locked. We’ll be keeping our eyes peeled for a Select-Trac WJ in the junkyard so we can nab the shifter with the correct pattern.
Lastly, we had to shorten...
Lastly, we had to shorten the NV247Js shift arm to work on the NV242J. Here is a before and after picture. It would be way easier to just get the factory plate from a 4.0L WJ with the NV242J. There are two places for the WJ’s transfer case shifter cable on the bracket underneath the Jeep. You will have to switch the cable from the upper to the lower hole to correspond to the shorter shift arm.