I'm a nubie, but have a good engineering and mechanical background. I have searched the various Jeep and 4x4 forums and have not been able to find a direct answer to a fundamental (for me) question about the function of the Command Trac transfer case (specifically 1996 XJ vintage). The question: When the transfer case is in neutral, are the front and rear drive shafts hard coupled? In other words, if the rear wheels are driven and the transfer case is in neutral, does the driven rear shaft force the front shaft to turn as well. The relevance of the question is that I need to flat tow my 1996 XJ that is equipped with an Aussie locker in the front Dana 30 differential. I'm trying to determine if, in neutral, torque is transmitted between the front and rear shafts.

I see that switching to 2wd decouples one of the front axle shafts via the vacuum decoupler. That makes sense whether or not the front and rear drive shafts are coupled in the transfer case in that this would reduce driveline friction. Looking at the transfer case the parts descriptions are inadequate for me to conclude as to possible decoupling of the front output shaft in the illustrations. My transfer case is NP231. Any help would be highly appreciated.

 

2Hi - rear wheels driven, normal driving, front wheels decoupled. 4Hi Front and rear coupled at same gear ratio os 2HI, use only on slippery surface ie dirt or snow, N TC diconected from rest of transmision, Good to use when flat towing the Jeep, Trans would be in park. 4LO is for when you want high torque, hills and such is Front and rear are coupled.

 

N on the TC decouples every thing.. Is the flat tow position.

 

Thanks for the clarification. After posting the question, I studied a copy of the Service Manual and discovered that I was incorrect in my description of the front axle on the 1996 XJ. It turns out that all XJ's after 1991 had non decoupling front axles. In view of that, the front drive shaft has to turn and be under a full torque load when the front wheels are turning. Consequently, the transfer case must completely decouple the front drive shaft from the rear drive shaft in 2wd and in neutral. I was also able to locate an engineering document on the NP231 transfer case that illustrates the power flow through the case in the various conditions of neutral, 2wd, 4Hi and 4Lo, demonstrating how the decoupling of the two output shafts occurs.

Therefore, the Aussie locker will have no impact on the flat tow-ability of the Cherokee, which was my original concern. In fact, it appears that the transfer case, key to 4wd, makes the 4wd command trac version of the Cherokee an ideal flat tow vehicle. The factory suggests drive shaft disconnect or dolly/trailering for the 2wd version when towed!

I began my path to the Cherokee XJ because I needed a tow vehicle to transport with my motorhome for access for local and offroad excursions. I wanted something light but highly reilable and preferably with 4wd capability. I was initially lead to the Suzuki Samurai and then to the Geo Tracker. The curb weight of the Samurai is 2057 lbs and that of the Sidekick/Tracker 2dr version is 2700 lbs. Their gross vehicle weight rating was 30% higher. They could only be flat towed for 200 miles before the engines had to be run in order to lubricate the transfer case. The 1996 Cherokee has a curb weight of 2927 lbs and the GVW is actually 60% higher (4,600 lbs.) and weighs less than 10% more than the Geo Tracker. Not to mention the greater power, larger size and capacity and poorer gas mileage. All in all, the Cherokee seems an excellent TOAD (TOWD) choice!

 

Thats why you see so many jeeps being towed behind RV's. They are Light and a Decoupling Transfer case. Also the Jeep TC has its own internal fluid supply and is self lubing.

 

I have towed a 90 tracker for probably a total of 40000km and never did I have to stop while towing to start it up. I recently purchased an xj to flat tow as well and as you figured they are ideal for flat towing and off roading.

 

I was just quoting the Suzuki and Geo Tracker Factory info on flat towing.