Hey guys, I recently bought a 98 ZJ with a 4.0I and Quadra Trac 4x4. It has the NV249 transfer case. It seems like they don't get a lot of love, and the VC's are notorious for being the culprits. I changed the fluid in the T case which was low and terribly burnt, thinking the VC is bad. However, before I go down that path I had a question about the ABS system. The ABS light stays on, and I'm not sure if that would effect the full time 4x4.
My question, is if the ABS system is malfunctioning, could the lack of information being transmitted cause the control unit to think its slipping and engage the 4x4 permanently? Or am I looking at two separate issues?
Also, I lifted the jeep and confirmed all the wheels were locked. However, the PF wheel can turn with some resistance and makes a chirping noise while being rotated. (Noticed this when coming to a stop and initial acceleration.) It looks new, but do you think it could be a bad CV axle.
I know thats a lot of questions. Any help is appreciated gentleman.
Also, I have an xj I plan on modifying for more off road trail stuff. The ZJ is meant to be the wife's daily driver, so I'm not looking to do any crazy mods / upgrades unless they are tuned towards safety.

 

The full time 4x4 on the ZJ Grand Cherokee is the same as full time on the XJ Cherokee im pretty sure if the lever is in full time 4x4 it is in 4x4 and ABS plays no part in that fact. Full time 4x4 on a NP242 for example just allows the front and rear driveshaft to turn at different speeds so things don't bind while turning but it is still in 4x4.

 

Let's get one thing straight. Full time 4x4 in a 242 t/case utilizes a differential gearset inside the case to allow front and rear driveshafts to operate at different speeds. The 249 is a constant 4wd t/case using the viscous clutch to accomplish the slippage necessary to achieve the same effect. As stated, it is CONSTANTLY in 4wd.

Part time in the 242 locks together both axles at a constant speed and should never be used on dry surfaces. The 231 in Cherokees (XJ) 4wd selection is also part time because it does the same thing. Low range in both are also part time.

There was a t/case, I think it's the 241, that has no shift selector and no low range. It works the same as the 249 and was made for people who get confused with the second shift lever.

 

Copy, thank you for the info. I thought it only engaged when necessary. Didn't realize it would stay in 4x4 when not needed. Any advice on diagnosing the ABS light or the CV axle?

 

The NV241 is the same as the 231 just more heavy duty.

 

Is it safe for my wife to drive if the VC is bad?

 

Two things can happen when the VC goes bad. The first thing is it fails to where it only has 2wd which isn't a problem for daily driving. The second more common failure is that it stays engaged and is scrubbing the tires when you go around corners, this increases wear on your drivetrain and tires, and also decreases your fuel milage, but you can pull the front driveshaft and drive around in 2wd like normal if that happens.

 

Thanks man, pretty sure the VC failed with it engaged. Hops when doing figure 8's and the outer tire tread is a little chewed up. Don't have a garage to do the 242 swap, so i'm gonna change the VC out and hope that resolves the PF axle issue as well. ABS isn't as big of a worry for me if it's not affecting the 4x4 operation.

 

I don't like ABS anyway, my XJ doesn't have it and I disabled it on my ZJ and truck.

 

You don't have a garage? You have to totally disassemble the t/case to change the VC so how are you planning to do that? You'd be time and money ahead to do the 242 swap.

I agree with 00t444e about the ABS. Yes, it allows you to still steer in a skid, but it actually increases the stopping distance when activated! Mine hasn't worked in 10 years and I have a piece of electrical tape over the light. I also have an educated foot!