Sounds like your Integrated Wheel End hubs are not engaging. Since Vacuum disengages the hubs, a leak shouldn't be your problem. You may have a stuck IWE solenoid like I do (see above post) or actuators that are simply stuck in the open position.

I suspect the solenoid. Disconnect the output line and see if it still pulls vacuum when the 4WD switch is engaged. If it does, then you need a new one. The 4WD switch is supposed to make the solenoid turn off the vacuum to the actuators.

 

Thanks for getting back to me about this. I have 2 new Actuators on the way, and picked up a new solenoid yesterday. Now, we're just waiting for the weather to clear so the work can be done...

 

I have a question. Forgive me for not going through every page of this thread to see if it's been answered but I'm really short on time. As you mentioned in your original post, a person could unplug the line at the intake and cap both ends to make the actuators lock in place until they could figure out what was causing the issue. Well, I did that and I STILL get the grinding noise from the front passenger side. Of course, I've driven this thing a while since my IWE solenoid went out but the sound wasn't very bad until just recently. So I FINALLY changed out the solenoid today, which fixed the issue of my 4x4 light not working but it didn't fix the grinding. Probably a dumb question now but could this be a sign my hub is screwed as well as the actuator?

 

I've just completed replacement of both actuators and the solenoid, which did, in fact, cure the issue. As I found while taking it apart, the passenger side was engaged, but the driver's was not. Getting the 6 bolts at the passenger side transaxle out was fairly easy with my helper standing on the brake, but he had to use a pipe wrench on the half-shaft axle for the driver's side. Once I had the driver's actuator out, it seemed to function alright, but there may have been a leak in the diaphragm. Also, closer examination revealed the beveled edge caused by an actuator engaging only partially and spinning.

If you are only hearing the grinding on one side, I would replace that actuator. It took me the better part of 4 hours to replace all of the parts mentioned, so it should be a 2 hour task for the one side. Get the front end up on jack stands with the engine off, see if the half-shafts turn when the wheels are turned. Without the vacuum of the engine to pull back the actuators, they should both be engaged in the hubs.

 

Well, thanks anyway guys but if I would have just jacked it up and checked it in the first place I wouldn't have wasted your time with my question. Jacked it up today, actuators worked fine. So I decided to give the passenger wheel a jiggle. BINGO! That thing had quite a bit of wiggle to it. Replaced the hub assembly and it drives like a dream.

Plus, thanks to xjcamaro89 and a few others here, troubleshooting any future issues should be a LOT easier.

 

I have a 2005 Ford Expedition that is making a loud noise from the front passenger side. It's not exactly a grinding, but best description I can come up with is a washboard type sound. It only lasts a few seconds and is very intermittent, usually at higher speeds and sometimes when making a slight turn or curve to the right. After reading this, we replaced the solenoid which did not take care of the problem. The vacuum appears to be fine. We have it in the shop and they have replaced the wheel bearing and the axle shaft. The noise is still happening, again very randomly. This is our family vehicle and I do not feel safe driving it. Any suggestions?

 

So I'm pretty sure my solenoid is busted but how much will my gas mileage be affected? I'm moving out west from NC and I want my truck to as fuel efficient as possible.

 

OK all just read this entire thread and still have a question...
I put my truck in 4hi last night just to keep things moving. Also went into 4lo for a bit. Dash lights work like they're supposed to. Ok so I try to put it back in 2hi and it won't go. 4hi light stays on. It'll go into 4lo and back to 4hi no problem but not 2hi. Tapped on tcase motor with a hammer, nothing. Truck stills puts power to all four wheels when switch is in 2hi (floored it on a gravel road).
What activates the dash light? The tcase motor or the iwe solenoid? If the tcase motor is shifting properly why do I still get power to all four wheels? Does the solenoid have to work before the tcase motor will shift??
Sorry for all the questions just need a bit of help here. Thanks in advance guys...

 

have a 2007 F150 4x4. I have had some issues with the vacuum as I had that grinding noise going on from the actuators. I replaced them and the solenoid. The driver side wheel hub was bad so it too was replaced. After all of that I was still having vacuum issues because it was not operating properly. I found 2 check valves that were bad. Went to the ford house and bought replacement parts. I got them installed tonight.
Here is where it is confusing me. I jacked the front end up and started the truck. The wheels will turn properly without the shaft turning. So I go to drive it and it is like I am losing vacuum because I hear the grinding noise. It sounds like it is coming from the passenger side. Not sure why it turns fine and no noise when I am parked and have it jacked up turning the wheel but then it happens when I am actually driving it.
Any thoughts or suggestions?

 

Thank you for that write up. A typical 4wd problem I heard these trucks have is the vacuum line coming off at the wheel. Which occurred to me during a snow plowing run. So my handy mechanic custom made brackets to keep this from occurring again.

 

I believe this is the same problem I am having with my 08 fx4 but the weirdest thing happens along with the grinding. My instrument cluster and my radio go out right before the grinding starts. Did this happen to anyone else? Can anyone explain this?

 

Hey guys, great posts, I have learned much about my 4x4 operation. I have been plowing through every post I could find about IWE's over the last few days after my 4x4 failed to engage but I still have a question. I have tested all the vacuum lines and everything appears good, the only malfunction I found is my passenger side actuator will not disengage but both actuators hold a vacuum and I still don't have 4x4 until I unhook the line from the engine. Is it possible that a stuck actuator could cause the other side not to engage at all? From everything I've read about the system it doesn't make sense to me that it would be locked on one side and not on the other with no vacuum leaks anywhere in the system. I dont really have the money to start replacing things I dont need so any help would be much appreciated

 

Sorry if this has been asked, im new here, and just bought a 04 f150.

When switching to 4H or 4L sometimes Ill have to switch back and forth a few times to get the dash light to go off or come on. Would this be caused by a bad IWE solenoid?

 

I appreciate all of the great posts and input on the thread! Awesome stuff! But honestly...I'm so freakin' tired of dealing with the stupid issue on my truck! I love my truck and the fact that everyone on here loves their trucks too but I haven't seen anything on anyone going to manual hubs and getting away from the IWE BS...
any thoughts

 

Well I replaced my actuators yesterday. The drivers side (which seemed to make all of the noise) looked ok and appeared to operate correctly. I replaced it anyway and then moved to the passenger side. When I pulled it out of the hub it came out in two pieces so I thought BINGO! Found the problem. I reassembled and went for a test drive. The noise was even worse??!!! WTH??? So I pull the check valves and the one at the solenoid is not working. I will get a couple of new check valves and see if this is my problem. I will also look over my vacuum lines to see if I have a plugged line. I just don't know why after replacing both actuators, solenoid, that my problem got worse?? The passenger actuator was completely broke in half so I thought I'd found the problem..... very frustrating I tell ya!
Do the vacuum boxes fail? I don't remember reading anything in this thread about them failing....