Dusterdude72

Hey guys, I hope I am posting this in the right section.

Ok I have an 05 F-150 short bed, super cab,5.4 v8 , auto , 4x4, 109,000 miles.

Mind you I have not had any prior issues with my 4x4.

We just got a good bit of snow dumped on us here in Michigan and its only in the single digit temps. I hopped in my truck, put it in 4 wheel high, light illuminated on dash showing it engaged and I could also hear the transfer case engage. Took off and my 4 wheel drive was working just fine, drove for about an hour and it worked fine the entire time.

Parked the truck, got out and went to get something to eat and when I came back I got in my truck and left and again my 4x4 was just fine. about 3 miles down the road I noticed I wasn't getting any traction ....like I was only in 2 wheel drive. so I cycled back to 2 wheel and then back to 4 wheel and same thing. So I then cycled it to 4 wheel low and when I drove I could feel I was driving in low range but still only with just my rear wheels spinning. I then put it back in 4 wheel high. (I can still hear the transfer case engaging between each selection and my dash lights still show what range I have selected).

In 4 wheel range on snow, If I accelerate and make my rear tires spin out and hold my foot on the throttle to continue spinning out....eventually (with my window down and head out the window) I hear what sounds like a grinding noise maybe from the drivers front ...at which point you can feel 4 wheel reengages and I get traction. Then if I let off the gas and come to a stop and go to take back off...I only have power to the rear wheels once again unless I continually spin my rear tires until the grinding noise up front happens at which point the front wheels engage.

NOW, here is the kicker. After I found this issue I went home and parked the truck and went inside for 15 minutes. I then went back out to the truck,put it in 4 wheel high and took off and everything was working perfectly normal!. I even tried to make it do it. I gunned the gas from a stop to try and provoke the issue. but I couldn't get it to do it. I even tried putting it in 4 wheel low and romping on it...and still everything was working perfectly fine.

Originally I thought maybe one of the auto locking hubs stripped out or something...or maybe the spline on my cv shaft. But now I am not to sure.

I have read things about the IWE solenoids,vacuum system, water in the system freezing causing issues,switches and other things but I am not sure. Hard for me to pinpoint the issue being that it was intermittent ( now I have a hard time believing it to be a mechanical issue such as a hub or cv because I would think that it wouldn't randomly fix itself like that).

Anyhow, I figured I would run the issue by you guys and see if anyone has had the same issue and if they know whats going on and what I need to do to fix it . (right now everything appears to be working perfectly normal. But if it happens once it could happen again and I would rather address it in advance than to have it happen in the thick of a snow storm.

Sorry for the long post guys, if you have any questions just let me know ,Thanks in advance!.

VTX1800N1

My guess would be water intrusion in the IWEs, freezing and preventing proper operation. Parking the truck for a short time allows for a heat soak in the hubs, temporarily relieving the problem.

See my how to here: https://www.f150forum.com/f72/how-di...72/?styleid=14

Dusterdude72

Thanks for all the information!.

I agree in that it sounds like it may have been an issue of something icing up and then the issue going away after having heat soaked. HOWEVER....you had mentioned that the IWE's were likely freezing up and and then the hubs heat soaked and then things worked again. I Just find it hard to believe that both IWE's froze at the exact same time and thawed at the exact same time (I could understand if I had only lost traction on one front wheel....but I lost traction on both front wheels).

That being said (correct me if I am wrong because I am no expert when it comes to this system) I would assume it would be further up the line....maybe in the solenoid itself? ....from my understanding there is a single vacuum line that runs to the solenoid and then further down T's off to both IWE's. Which If I lost the function of both IWE's (or atleast lost partial function being that there was grinding noise as it attempted to engage and would then engage under harder acceleration). I would assume it would be somewhere in the single feed portion of the vacuum line that supplies vacuum to the dual feed further down the line.

However....also from what I read I see that if the solenoid has issues that the 4x4 indicator light on the dash could stop working (mine still worked fine) so I am not sure if that's always the case or just a possible issue that could result from the solenoid failing. or maybe that issue wouldn't be present if it wasn't a result of the solenoid actually failing rather than it being an issue with moisture buildup in the solenoid/vacuum line freezing and causing issue.

Sorry again for the long post, and please don't take anything I have said as second guessing your assumption of the issue....not the case at all, just brain storming on the problem and throwing out possibilities.

IF anyone else has anything to chime in with please feel free to do so.

I think my first steps will be to jack it up and run a vacuum tester on everything to make sure its all up to snuff. blow out the lines and maybe swap out the solenoid being that it had a TSB put out for it anyways and the new version apparently comes with a rain hood to avoid issues with it.

Thanks again.

VTX1800N1

The front differential is an open diff. So, if just one of the IWE/hubs has a problem, you will get no pull at all from the front end. All the power will go to the disengaged IWE.

Dusterdude72

DOH!.

Didn't even think of that!.

Thanks again, I guess I have some diagnostic work to do and see what I come up with. But will likely be tricky to come up with any clear answers being that its likely a water/freezing related issue that might be hard to duplicate.

Dusterdude72

Another quick question though. I BELIEVE I was hearing the grinding noise on the drivers front. Would that indicate the issue would be with the IWE on the passenger side?...or driver side?.

I have done alot of reading on the issue over the last few hours but it seems like I read something that said if the IWE on one side stopped working that the opposing side would try to engage causing a grind noise. Sorry to bug you with more questions....you have already been a great deal of help with the info.

VTX1800N1

It depends. Read over that link I posted. If there is water in the IWE, it might freeze and prevent the spring collar from moving. If there is water in a vacuum line, it can do the same by preventing full vacuum from reaching the IWE. If there is a vacuum leak on one side, it can cause grinding in the other side as they share a common vacuum feed.

Dusterdude72

ok thanks again. Ill report back after I have looked it all over real well sometime this week.

VTX1800N1

If you find water in the IWE or lines, the most likely source is the solenoid on the firewall behind the battery. If it doesn't have a hood over it, it is the old style and should be changed.

Dusterdude72

Noted, Thank you sir.
I will likely just get 2 new IWE's and a new solenoid and blow all the lines out. Then I will have the piece of mind knowing everything is up to par. Plus I would hate to put a new solenoid on it and there still be moisture in the IWE's and lines and recontaminate the new solenoid....or likewise install a new IWE (or both) and have the lines or old solenoid recontaminate those.

But first I am going to give it a good combing over and make sure all my lines are good and see what the vacuum gauge has to say.