Bad link, sorry.

 

Thanks for the updated TSB, John. I printed it out and will take it to the dealer as I can still feel the grinding with hte new YG360 check valve. Anybody know what the difference is in running in 4A compared to pulling the electrical connector at the solenoid and/or going with the eliminators from RCV?

 

You're welcome. Pulling the electrical at the solenoid will lock in your IWEs, but not the transfer case like in 4A. Only difference is the TC.
I try to let guys know that when they get the grind of death, to either pull the plug, or throw into 4A if equipped.

The eliminators certainly cure any IWE problems, nothing wrong AFAIK, I prefer to have it as built, since I sorta kinda know what to do with these things. NO, I'm NOT an expert on anything.

 

So, when I run in 4A, I can really feel the wheel pulling hard back to center....will I experience that same feeling with the eliminators? Also, when I leave a stop in 4A, it pulls a little to the left( I guess that means the left IWE is engaged/engaging)???


I'm the same way, I want to fix this so it works as it was designed to do....but if that original design is flawed to the point that it will always fail eventually, then I'll do a workaround.

 

What is happening in 4A, the TC is engaged allowing power to be transferred to the front diff, it all depends on the fluid clutch in the TC as to how much power, or none, will go there, also allows slippage so you can turn without binding anything up. Think of it like the differential in your axles, your axles become the wheels on either end of the axle. In fact, TCs used to be referred to as "interaxle differentials", could act like a locker, or an open diff. In 4A, it acts like an open diff, in 4H/4L it acts like a locker.
Now, by just pulling the power at the solenoid, the IWEs will engage, but unless you switch to 4H/L, the transfer case stays out of the picture.
What you're feeling in 4A, is simply which wheel is getting the power in front, because that's an open diff on most trucks.
By replacing the IWEs with that eliminator, you are actually doing the same as when you just pull the power, except now you've spent XXX$ on the eliminators. I will never tell a guy to spend or not spend, that's up to them, but IMO, it's free to just pull a plug, less labor, and really, you're doing the same thing the eliminators do.

I think I answered your ??? If not, let me know.

Here's a very good video on how the TC works. Never mind it's a Raptor, the 4A like you have is the same TC.
Ford F-150 Raptor 4WD Explained - Raptor Has 4WD and AWD

 

No it doesn't engage / disengage. When you're in 4A or if you pull the electrical connector, it drops vacuum to the IWE's and they engage and stay engaged untill vacuum is reapplied.

Unfortunately, all the work-arounds have a downside. Running in 4A all the time reduces fuel mileage, adds a bit of weight to the steering, increases front tire wear and makes the steering a bit heavier. Pulling the electrical connector (or installing the IWE eliminators) decreases mileage a bit but not as bad as 4A. You've got a bunch of hardware in the front axle and diff whirling around all the time unnecessarily so there's more wear and tear.

Come on Ford, it shouldn't take an engineering department full of whiz kids to come up with a vacuum operated IWE that works - the Super Duty trucks have had vacuum operated / manual hubs for years that work just fine.

 

Thanks guys. Sounds like I should pull the connector until I can fix it properly.

 

I think that's a good idea, likely prolong the life of the IWEs.

 

I’m not so sure they’re not gone already. The previous owner had no idea that they were grinding. At least they won’t get any worse until I can get some time to thoroughly diagnose.

 

Oh, that wasn't nice. When walking through a parking lot, every so often I hear the grind of death coming from someones 150. I just keep walking and mentally shake my head.

 

Since you use 2WD 90% (or more) of the time, am I the only one who thinks the zero-vacuum condition should be disengaged for the IWE? Sure, you'll run into that situation where you need 4WD, and the IWE won't engage, but isn't that better than having the grind of death?

 

That would seem to make sense but you want the system designed to fail in the most advantageous mode. If lack of vacuum disengaged the IWE's then a torn or cracked vacuum line to one wheel would effectively leave you stuck in 2WD. If you look under the truck at those vacuum lines going to the hubs it doesn't take too much imagination to picture an errant branch ripping one out off road.
I still like the system the Super Duty trucks used. If all else fails you can always get out and dial in the hubs.

 

PupnDuck is correct. Vacuum disengages, lack of, engages.
Ya, I'd like some manual hubs too, but the 150 is basically designed to be a large, nice car. Mr./Ms. office type might muss up their Dockers if they had to manually engage the hubs. Let alone their LL Bean hikers.

 

i agree to the same

 

Saw this thread was still being posted to(edit: by a spammer now that I check), wanted to share my experience and solution. Don't hate me if this has already been suggested or is the common fix to the problem. Also wanted to include pics since browsing quickly I didn't see any.

I had the IWE vacuum issue with my '06. Long story short, after 5 weekends diagnosing, replacing some parts, diagnosing, getting frustrated, and replacing everything, I decided to go the route of leaving the vacuum "off" for the IWE actuators at the hubs. Luckily I was capable and determined to do all the work myself, so the cost for 2 new hub assemblies and 2 new actuators was somewhere in the range of $500 (yes I used Amazon, yes I used Dorman actuators, yes I used whatever brand hub assemblies were lifetime warranty - it all worked years afterward after my "modification" and worked the day I sold the truck).I couldn't imagine what the cost would have been to have a shop do the work - but I will find out because I am curious on how much I "saved" doing it all myself. Later this week, look for an edit to add in the price of having a shop do the work.

As I have read in the '04-'08 forum, once you hear the grind, it's too late. Actuator and hub assembly are shot, and most likely both sides. Vacuum leak to one means vacuum leak to the other. The teeth aren't very large/deep and any grinding is going to round them out and wear them down fast. Thus why I said "fvkk it" and did both sides at once.

My solution at the time was to just leave the vacuum line unplugged at the actuator and let the axles spin freely with the wheels all the time. I didn't care about the slight (if even noticeable) decrease in fuel mileage, I just didn't want to have to deal with a vacuum issue in the future. "But what about dirt/grime/water getting into the actuator and tearing it up?" A good question, one I had as well. So, on my '16 I simply unplugged at the other end, where the solenoid is. I put a "rubber vacuum cap" or whatever they're called on the end of the hose and over the solenoid nipple I unplugged it from (red circles), then zip-tied the two hoses together (blue circle) gently so the one I unplugged didn't fall down in the engine bay. $3 for a pack of various sized vacuum caps from Auto Zone and 10 minutes of work, including the well-deserved beer afterward. Pics show the finished product, solenoid is on the upper part of the firewall, driver's side. The slight unnoticeable loss in fuel mileage is worth the peace of mind knowing that I won't have to go through the mess I had to deal with on my '06. Hope this helps someone out.