Hi All,
Been here many times for help before but this is my first post. Hopefully someone can help. Sorry for the long post, just trying to be as descriptive of the issue as possible.

I have been having problems with my 4x4 disengaging. I have the shift on the fly dash **** for the 4x4. It engages fine while driving although it seems like it has been louder in 4x4 than usual. However, when I disengage the 4x4 it is not coming out the way it should. I should be able to shift in and out on the fly (under 45 mph) but now it is sticking in 4x4. The dash light turns off, but the 4x4 doesnt disengage until I come to a full stop. Sitting in my driveway I can turn the switch on and off, there is a click under the truck and the 4x4 switches on and off fine. We had a storm a couple of weeks ago that brought some brutally cold weather, flipped the switch once I got on the highway and the road was clear but it didnt disengage, I pulled over on an off ramp stopped and gave it a few seconds heard it click, got back on the road and had a wicked pull one of the fronts was still locked so I pulled over again it clicked and all was fine. Later that day I tested it and they both disengaged (still requiring me to stop) so I chalked it up to the below 0 temps that morning keeping one of the hubs locked up. We had another storm last night and I was in 4x4 for the ride home. Getting on the highway this morning it wasnt too bad so I stopped before getting on and turned it off. It didnt disengage. Pulled over a couple miles up stopped and it still didnt come off. The roads were wet and sanded so just let it be until I got to work about (about 30 miles) it wasnt until I pulled in at work and turned the wheels all the way left then right that i felt it finally disengage. I turned hard in the parking lot to see if it would bind up and that actually is what seemed to do the trick in freeing up the hubs.

I have done a few searches and come up with possible solenoid or actuator problems. My gut is telling me probably the actuators and hopefully not the hubs. I am fairly handy and willing to check this out but this is new territory for me. Removing the brake calipers to get to the actuators and hubs does kind of sketch me out since i havent done much with brakes in the past and stopping is kind of important! Long story short, I am hoping someone can help me narrow down the problem before I get into tearing things apart. I should also mention my truck has about 115k on it so I am also wondering what kind of maintenance I should be looking at for the 4x4 system at this point.

Thanks

 

either your T-case motor is hanging up or you have a clogged vent line...

 

I had a similair problem with the 4x4 only partially disengaging. You may want to replace the IEW solenoid. If moisture gets in the vacuum hoses and freezes, you'll have trouble. I also replace the vacuum reseverior, it's located behind the battery.
I had to replace a wheel bearing because the gears were ruined. Of course the one I put on was defective! It was missing a seal, therefore it wouldn't hold the vacuum.
You should start with the soleniod and work from there. Good luck.

 

Thanks guys. I will check those out. How can I tell if the solenoid is bad?

 

The IWE solenoid controls the vacuum to the IWE's tells it when to provide it and when to vent it..like stated above if...the vent line or vacuum line got water in them and it turned to ice...it would clog them and prevent them from working correctly..you really need to perform a vacuum test with a vacuum pump at each IWE to tell if all's working correctly..or you can replace the solenoid which runs $30 bucks or so...to me it seems to be working...you can engage but not completely dis-engage...depends what you want to do...troubleshoot or throw parts at it...

 

Thanks for the advice. partsgeek has the solenoid for like 20 bucks and since we know the old one was flawed I might just swap it out anyways. I suspect water in the lines because I am only using 4x4 in the winter and it seems like the colder it gets the less responsive it is. I will swap out the solenoid and test the lines.

which brings up 2 questions : where can I get a cheap vacuum tester since I dont see using it more than once maybe twice in my lifetime and 2 Can I test the lines from the solenoid end, or do I have to test them at the wheel?

 

I've always been told to come to a complete stop before engaging or disengaging 4x4. In any vehicle. I think it reduces wear and less likely to break something. But that's just my input man. Hope you can get the problem fixed!