TNF150.... Many thanks for your time to take the pictures, post them, as well as the techical PDF files, enabling us to upgrade our IWE solenoid and replace our vacuum operated actuators. We have a couple of questions:
1. The technical manual PDF page said to replace the 3 locknuts (the spindle axel locknut, the upper control arm balljoint spindle nut, and the tie rod end nut). Ours went back on, almost as tightly as they came off. We re-used ours. Did you find it necessary to discard and replace your's?
2. We literally had to tie a nylon strap around the axle, and secure it to the lower control arm. This strategy was our saving grace, while trying to wrestle the axle spindle out of the hub. Even though we let down the steering knuckle, it was still quite a struggle to "clear" the hub, so we could slide the new actuators over the spindles and onto the housing. How did you hold or pull your system backward, toward the differential, to remove and swing away from the hub?
3. We used Lubrimatic's moly EP grease to coat the conical gear in the hub. The actuators came with some type of green grease on them, so we obviously left that on them. The moly EP says it is recommended for sleve, ball and roller bearings, ball and universal joints. It says it is not recommended for disc brake bearings, so we used some of the green grease from the new actuators, to re-coat the roller bearings that the axel spindle rolls on, inside the hubs. What type of grease do you use?
4. How often should the bearings inside the hub be repacked or replaced?

Thanks for your time.
bstephens00

 

This is a great thread! After reading it I think I have a similar problem. First off let me say this I bought the truck this past summer, 2005 f150 lariat 4x4 83000 current miles. Here is the issue that I am having when I go to place the truck in 4hi or low. Light comes on like it should I sometimes here a thud or bang, but nothing front wheels are not at all engaged. I found this out the hard way in this past blizzard we had. My neighbor didn't believe me and I wanted to see what was going on for myself. So I told him to drive while it was spinning in the snow. Standing in front of the truck I heard what seem to be a grinding noise coming from the front, but still nothing no 4wd. What is your guys diagnostic? Thanks in advance for your help!!!
Jeff

 

It is impossible to say for sure with the info given.......put........it is most probably one of three things.
1) You have a damaged actuator/IWE (if one is damaged.....not engaging...........your front axle will do nothing)
2) Your vacuum solenoid is not working properly
3) You have a vacuum or vacuum line issue

My best guess..........is 1).

TROUBLESHOOT:
-Jack up the the front end (both sides)......get both wheels off the ground.
-Use jack stands to secure
-Block the rear wheels
-Start the engine and put in neutral
-Turn each front wheel and check to see if the half axle turns on that side.......the half axle should not be turning.
-Now move the 4WD switch to 4HI
-Again turn each wheel. The half axles should turn on the side where you turn the wheel. If the half axle is is not turning, your actuator is not actuating (not engaging). This will result in "zero" front axle or no 4WD.

I would guess that one of your half axles will not turn.............which usually indicates that your actuator is bad (but......you will need to check vacuum lines at this wheel to make sure your vacuum is OK).

I bought a vacuum gauge kit from Advance Auto or O'Reilly. All I did was hook the gauge on one end of the kit's hose, and put a fitting in the other end. Pull your vacuum line from the IWE (it is a 2-line system......the small line is simply a vent.....the large one is vacuum line) and shove the vacuum gauge hose fitting into the IWE vacuum line. With the engine running and 4WD switch off, I meassured about 20psi vacuum at each wheel. You should be at least 10 or more (it does vary somewhat). Now flip the 4WD switch to 4HI......you should see the vacuum release go to 0 psi (or near) vacuum. This process will tell you if your vacuum system is performing properly at each actuator. In 2WD you have full vacuum at each wheel, then when you your go to 4HI the solenoid should act to release the vacuum at each IWE and it engages. If there's a vacuum problem.......start with the solenoid (pull the line at the vacuum solenoid and check the vacuum with the gauge to make sure your vacuum is OK). If your vacuum line coming to the solenoid checks OK, replace the solenoid. If you have no vacuum coming to the solenoid......start tracking the vacuum system and look for any leaks, improper connections, etc.

This whole process can take as little as 10-20 minutes. You should easily be able to nail down which actuator or if the vacuum solenoid/system is the problem.

 

Thanks for the help I will let you know the outcome I am using a lift today

 

the truck has been fixed it was the IWE actuators replaced both of them. While I was at it did a brake a rotor job, many thanks to all that helped with info!!

 

Can this problem occur without having a 4x4, I have a humming noise but I dont have 4x4 on my Ranch.

 

This is obviously an easy fix, however I stumbled upon this topic this morning and wanted to share my experience as well.

I was leaving the grocery store, and i heard the same grinding / scraping sound everybody was talking about. After poking around on the forums to understand how the 4 Wheel / IWE system works, I started small.

1) Checked the solenoid on the firewall for tight connections or excess moisture.
2) Checked the passenger actuator to make sure the vacuum line was not broken.
3) Checked the drivers actuator and there was the culprit.

The vacuum line on the passenger side had a lot of slack in the line, however the line on the drivers side had very little slack on my truck and had slipped off of the actuator.

I reconnected the line and took a test drive and voila, problem fixed.

Moral of the story,

- Read the forums thoroughly
- Start at one end and work to the other.
- Pray to whomever you pray to that it is something nice and easy.

Thanks to everybody for their explanations of the IWE system and the diagrams... saved me hundreds of dollars!!!

-M

 

I have a 2008 with 20000 miles. Mine started doing it a few weeks ago.
First it did it twice in about a mile then stopped for a couple of days. Then did it again once, seems like it is the right side.
Today I just pulled the main vacumm line off the intake side and plugged it for now! tired of hearing the noise and do not want to do more damage before I get to dealer. Why does it come and go so much?

 

Great thread ... but question going back to page 1 of the thread.
Would it not be far better to find the vacum supply line where it comes off the intake or where it tees off the PB Booster and cut it beyond the booster and simply plug it until you got it to service?

If you run in 4x4 on hard sufaced roads you are going to have a tightly bound up driveline that may break something at worst, and create a lot of heat and stress at least.

Cutting the line and plugging the cut end past the brake booster deprives the IWE of all vacum thus engaging the IWEs and still allows one to drive in 2x4 thus not putting the driveline in a bound up stress. Plug the cut end nearest the motor or brake booster tee so to prevent a huge vacum leak and preserve vacum to the brake booster.

The cut ends can be put back together with a barbed splice fitting or replaced with cheap rubber vacum tubing.

 

Just a comment to tbear.. You do not need to cut any lines!! You can just get down and remove the vaccum hose from the acuator at the wheel. Just plug it there and when fixed all you have to do is reapply the line.

Just do this for one or both if they are making noises and you engage the hubs fully but can stay in 2 wheel drive.

 

Ok, so here's my question... why not just remove the vacuum system from the equation? From the post above it sounds like you can disconnect the vacuum line and permanently lock the IWEs. Right? And if you keep it in 2wd mode the differential is open to the front, so the axles will spin but the diff is open, so no power is going to either front wheel. So you essentially have a system like the pre 04 4wd.

Im not sure about there being a differential there, but from first page OP suggests that switching to 4wd engages the IWEs by releasing vacuum and simultaneously engages the drive shaft to turn the front axles. So it sounds like the switch does TWO things, but only one is strictly necessary to get 4wd, and that is locking the drive shaft to get power to the front. The IWEs sound like they are superfluous, they are only there to reduce rotating mass on the front wheels and save a MPG or two.

Then select 4wd hi or lo and it provides power to the front wheels, and since they are already locked there is no need for the vacuum system at all, right? I would imagine this could cause increased drag, so maybe some change in steering feel, and gas mileage. But I can't think of any reasons why it wouldn't work.

But then, I am FAR from an expert. Any thoughts from those who have had theirs torn down already? Another option is to look at how hard it would be to switch to a "posi-lok" style cable system that does the same job as the vacuum system, but manually.

Thoughts, comments, flames?

 

Hey Wildvodka,

I also am far from an expert but when I had trouble about a year ago I read quite a lot of material from actual service manuals to everything posted all over the internet. Of course I found this thread eventually and fould it very useful.

I replaced my acuator myself with no problems.

I think you are correct about the vacuum system and that it is only there to prevent some rotating mass and save gas mileage. There is a 4x4 motor of sorts that has to engage the axls to provide power and 4 wheel drive. These axls are being engaged and disengaged at the wheel by the vacuum system to either spin them or not. They then get engaged at a transfer case to provide power to the axls.

By the way I never did have any grinding but thought there was a small vibration at my passenger side wheel. My vacuum system was working perfectly when checked. Here is the easy way to check your acuators:

With truck off, in 2 wheel drive and parked get under vehicle and try to rotate the axls to the front wheels. They may turn a little but then lock. This is because there is no vacuum and the acuators are engaged at the wheel. Start the truck, leaving it in park and 2 wheel drive and try again. You will notice that the axls should move freely because with vacuum applied the acuators are pulled away from the wheel disengaging the axls. They should rotate freely or if there is a little binding or one wont turn you have yourself a acuator problem that may or may not have been caused by the vacuum system.

 

Ok ive been trying to read up on this but what exactly is the actuator and where can i find it at? Ive been having this grinding noise after installing my lift and i know my pass side was fixed i guess by the iwe solnoid. So my question is that there is only 1 IWE solnoid correct? Also if there is only one im getting the grinding noise and havent really driven the truck so i just need to replace the actuator and see if that fixes my problems then if not go with the actual hub assembly itself right?

I did what was said in the above post by turning the half shafts with the vehicle off and they turned slightly but locks and then turned it on and moved freely. But cant hear or feel any binding so this tells me what? I tried taking of the vacum lines on the driver side to see if it would stop and still grinding. I dont really know where to start or what to replace? I might just take it to another mechanic after spending 97 at ford for them to tell me both my hub assemblies needed to be replaced.

 

Te solenoid is behind the battery on the firewall. It has 1 connector with 2 wires in it, and some vac lines. That is the cheap piece that I replaced for $17 from my local dealership. I never replaced my IWEs but this fixed my grinding noises.

When at full droop my half shafts will not turn due to having the leveling kit and making the angles more extreme when the tires are off of the ground. They turn fine though when under normal and not so normal driving

 

So there is only one solenoid correct? I located it but what do i need to do with it now? It was replaced like 2 1/2 weeks ago and it stopped making the noise on the passenger side but after installing my Rize lift its making noise on the driver side. I can turn the axle shaft while truck is turned on but with truck off it locks. But i took off the vacum hoses and its sucking air in to them which is good i guess but how do i measure them? Do i take off the hoses and then out the vacum gauge onto the hub outlets or on the hoses itself? Also sense they are sucking air in does it mean its more than likely my actuator or hub assembly?