Griff94

i have an issue that when I put my XJ in 4x4 it will go in fine but I can't get it out. The lever will go down but the front axle stays engaged. It only kicks out after I drive about 2 miles, and I haven't checked yet to see if putting it in reverse kicks it out. Also, when it's' in 4x4 my front end makes a weird deep toned whining noise. My last XJ didn't do this so I'm not sure if it's normal or not.

Some info: NP231 Transfer case, Dana 30 front axle, and Chrysler 8.25 rear axle (not sure if the rear axle is necessary but here it is anyway)

Griff94

OK, after some research I have found out the transfer case issue is because of either low fluid, a cracked vacuum line, just another "Jeep Thing", or even just because it hasn't been put in 4hi in a bit.

But that still doesn't answer the front end whining. I really need to find out if this is normal or if something is wrong but I can't find anything on it

cruiser54

Has nothing to do with vacuum first of all.

Never hurts to check you fluids......

Here's how you shift a Jeep from 2Hi to 4Hi or the other way around. First of all, do it at speed, 25 MPH or higher in a straight line. Let off gas, pull lever, tap gas, let off gas.

Griff94

I thought that the transfer case was controlled with a vacuum line that ran off of the engine? Oh well, just another thing I'm wrong about.

Also, I usually do shift from 2hi-4hi exactly like you described. So it's narrowed down to either the fluid or just a "jeep thing".

Do you know about the axle whining noise? I should have clarified that when it does this it is pretty loud, it's not just noise from the front axle being engaged I think it might be something else. The best way I could describe it is if you have ever been on a school bus and the driver hits the brakes and it makes a loud whining noise that starts high pitched and gets lower as it slows down...well that's exactly what it sound like in my front axle.

cruiser54

Checked the level in the front diff yet?

andyg

My case will go into 4hi whether moving or not. I would make sure the linkage is properly adjusted. The lock down for the linkage could slip a bit if it wasn't fully tightened.

cruiser54

Some whining is normal in 4wd mode, and yes, sometimes they will shift easily when stopped, but for the most part they don't and weren't designed to.

Griff94

Have yet to do that...What's the best way of doing it? Just shoving a flat head under the plug, popping it out, and sticking your finger in the hole to check the fluid? My buddy told me to do this...but he isn't really the best with mechanics and I personally never dealt with something like this.

Again...I'm not the best at vehicle mechanics, so is adjusting the linkage something I could easily do on my own with some instructions or should I just take it to a mechanic and have them do it properly?

Mendax13

wait. your supposed to go from 2hi to 4hi while at speed? ive always stopped to engage it...

cruiser54

Absolutely. The NP231 transfer case as well as others were designed to be shifted "on the fly" as Jeep put it in the owner's manuals and sales literature.