Drive shaft is too short.
 

I have a 1995 Jeep ZJ, 4.0L I6, it has a NP242J transfer case and the drive shaft once seated in the rear yoke, it slide's into the output shaft a quarter inch, maybe less. It has a 3.5" RC suspension lift and the Tcase is dropped 3/4's of an inch. I cannot figure this out, should I have the drive shaft lengthened at a driveline shop? Do I even have the correct Tcase for my vehicle? Any help is greatly appreciated, thanks!

You have a V6? Cool. Most of the other ones are inline 6's. You have this jeep, but have you driven it like this? How long has it been like this? Yes 1/4" seems far too little for the splines to be contacting the output shaft, if I understand the question.

Welcome to CF!

Yes, your shaft needs to be lengthened or replaced with the proper one. You probably have the shaft from a 249 which is a little shorter PLUS the lift. If you put any torque on it now, it will split the splined end and come out, smashing everything nearby if the jeep is rolling. You should have at least 2" into the t/case with the wheels hanging OR with it on the ground and the shaft slid all the way in, you should have to pull it out about 1.5" to get the u-joint straps on, maybe more with the lift.

This might be the setup that needs a SYE and a shaft with the splines in it.

SYE=slip yoke eliminator.

What year was the T/case made? Look at the red tag.

I never understood why owners would spend money to lift their jeeps only to lower the trans case. I guess it looks cool and saves money but creates other issues.


like dave posted you really should install a SYE kit and new drive shaft. the ZJ I purchased did not have the SYE with a 6" lift (no trans drop) and vibrated more than an all girl porno set. if you don't want to spend the money you might get away with lowering your lift and keeping the shaft but to do it right a SYE kit + shaft is in order.

The year of the case is the same as my vehicle, its a 95, the transfer case is a Np242J

Jon-d, the reason for dropping the t/case is to try to keep the driveshaft as straight as possible to the rear axle because the lift increases the angle enough to create vibration. Personally, I don't think it helps much except maybe for a 6" lift. It actually INCREASES the angle to the front diff.

So, TJ, is this a t/case swap or what? My 97 had a 4.0 and 242, but it had a flange-mounted universal on the back of the t/case. IDK if this was factory or not because it had 3 owners before me. It was stock height also. My WJ also has the 242J, but it has the exposed rubber boot without a tailshaft. It doesn't have the speed sensor in it either.

Been doing a little research. It seems the 231 and 249 both have tail housings and the 242 doesn't. The rear driveshaft splines are external with a rubber boot covering it. It must be my 97 had the old hack&tap SYE on it when I got it. I never paid much attention to it when I had it. I only removed the rear shaft when the diff blew up.

When I bought the Jeep it had the 242J in it, the case went out and I started searching for either a used one or a rebuild kit for it. I bought one from the boneyard, and put it back in. When I went to reinstall the rear shaft I found that it was nowhere near long enough. So I measured it, then went to the scarpyard and found a bunch of Jeep ZJ's of the same year as mine with the 242 case, all shafts were very close in length. I feel my problem was the output shaft, the previous owner had a longer output shaft on the original case, which is why it fit before, and not after the new case was installed. I ended up just taking the shaft into a driveline shop and they added the length I needed along with some very heavy duty U-Joints.