I've been having problems with my 4wd engaging; I did some troubleshooting, and here's what I've found:

1. First, the vacuum lines were disconnected. I checked them for vacuum, which they have, and I put them back, but they're really easy coming off. I though of using RTV on it, but I'd rather not. Anyone else do something with their's to keep them from coming off?

2. After reconnecting the vacuum lines, I get the part time 4wd light.

3. I know its going into 4-lo because the rear tires will turn against the parking brake and the front driveshaft turns as well. However, in 4-hi I'm not sure; the front driveshaft doesn't turn; is this normal?

So, any ideas? I'm pretty sure it is something in the axle, or more specifically the part that engages the axles. But, I don't want to pull anything apart until I've eliminated everything else.

 

the best thing to do is called Posi-lok. My 1988 YJ did the same crap this made it nisce. no more vacumm to worry about it's either on or off and you can have 2wd low as well http://www.jeep4x4center.com/product...?number=PSL900

 

A good method I came up with to keep the vacuum lines on the front axle vacuum disconnect is to use zip ties. They keep them on securely and are removable if need be.

I'm not to clear on your 4LO/4HI troubleshooting. You say in 4LO your front driveshaft turns but, in 4HI it doesn't?? That really isn't possible. the 2WD to 4WD shift is done as soon as you shift out of 2HI and into any other position of the TC shifter. You actually have to shift into 4HI before you can shift it on back into 4LO. It's pretty much impossible to have working 4LO but, not 4HI with the NP231 or NP242 transfer cases used in the XJ.

 

What I was trying to describe was that I saw the driveshaft turn in 4-lo, but when I looked at it in 4-hi I didn't see it turning. It didn't make sense to me either.

 

Are sure that when you slid the TC shifter forward into 4HI that it was in fact in 4HI and not 2HI. There is a very small difference in shifter position between 2HI and 4HI. If your linkage is at all worn you could actually be in 2HI when you think you are in 4HI. If you were mistakenly in 2HI that would explain your front DS not turning when you thought it should.

 

Personally, i completely got rid of those big black rubber connectors that bring all 3 lines together and just used pieces of vacuum hose to connect them to their corresponding colors. Worked like a charm and my 4wd works great.

 

I got rid of the the whole vaccum mechanism and built a cable operated actuator for my XJ.

 

cable is deff. the way to go go whether you buy it or make it it is way more reliable than a vacumm line any day of the week

 

Granted, however 2 bucks worth of vacuum hose sure ended up being a great deal for me.

 

Posi-Lock: $200 from most 4x4 vendors. "Buck" homade Posi Lock: $40 for all the required pieces and a couple hours of my time. It has never failed me in the four years I've been using it.

 

I know I was in 4 because I got the light

 

what did you have to do to make it? i assume it must have been easy....

 

The cable sounds like a good idea, but that will come later for me, I think. I'll probable do the zip tie thing for now.

 

How did you do that I would like to do the same thing don't trust vacuum very much

 

I have a write up in the XJ write ups section and there are a few pics of my cable axle posi locker in my pictures section on my profile page. The pics are small but you can get the basic idea. The heart of the whole deal is a hand throttle and cable that can lock in any position that I picked up at my Napa store for $30 bucks.