Originally Posted by DonJacobs (Post 4176242)

Folks - I have read thread after thread on the IWE dragging noise and took the easy, least expensive option first - I replaced the vacuum solenoid. I had the noise almost all the time and thought this cured it. After about 2 miles and a 90 degree right turn, the dragging sound of gears trying to engage came back and is just as frequent as before. Well, the $25 experient was not a bad experience. Does anyone suggest next steps for troubleshoot / repairs this before I do-in my entire front end?

Originally Posted by wildvodka (Post 4139860)

Thank you for the input so far guys! This is really encouraging.
@Tbear - one of the things I looked at before I read about the IWE was the "posi-lok" system made for previous generation f150s. It replaces the vacuum actuated system that engages the front drive shaft with a pull cable that gets routed into the cab.
Now, for your particular scenario I think such a system could be worked out if your were comfortable with some fabricating and making some permanent changes to the IWE system. It might be possible to rig up a system that pulls or pushes the IWEs in and out with a cable. Essentially the way that a mechanical parking brake works. Its a cable running to a center mechanism between the two wheels that pulls or pushes on the two sides equally.
With such a system the 4wd computers would all think everything is working fine, solenoid and all the vacuum stuff is still intact, just not hooked up to the IWEs. Instead the IWEs are manually controlled from the cab.
This would be the "next step" after seeing how simply locking the hubs by disabling the vacuum system works. Locking the IWEs is simple, just plug em up, but this would require some fabrication and more knowledge of the internal IWE workings than I have. But I'd love to see someone try it! Heck, make it a kit. I'd buy one.
Cheers!

Originally Posted by wildvodka (Post 4138852)

Hey all, I was following a thread on the IWE problems associated with leaking or otherwise malfunctioning vacuum system, and I had a question about a permanent fix.

Has anyone tried simply disabling the vacuum system entirely? You can block or plug the vacuum line at each IWE, which will permanently lock them.

So hear me out...
By locking the front hubs permanently you will cause them to always spin the front axles, and turn the front differential. However, unless the truck is actually in 4wd mode the front diff gets no power supplied to it, because the front driveshaft is not engaged by the transfer case. So, you will get increased drag, which may adversely affect MPG, and there is a slight possibility that you will lose some performance due to drag on the front wheels. However, I can't see that it would be that bad. Certainly it wouldn't be any worse that the pre 2004 models with 4wd, right? Because that is essentially how their systems operate.

My understanding is that the IWE are only there to decrease drag on the front drive train when in 2wd to increase fuel economy.

From reading the document on "principles of operation" for the Ford 4wd system, it seems to me that two things happen when switching to 4wd. First the transfer case shifts over to engage the front drive axle, while it does this it also uses a clutch to make the front drive axle match the speed of the rear drive axle. If the axle is already turning because the front hubs are locked, then this should be unchanged from standard.
Then it locks the front hubs using the IWE. Since they are already locked, this step is unnecessary. There would be no need to change any components, the vacuum system would still go through the steps to lock the IWE, just nothing would happen.

So what you would be left with is a system that only has the transfer case and its components as moving parts when switching to 4wd. No worries about water in the system, no problems with vacuum leaks.

It just seems to me the IWE system is superfluous, it serves no purpose other than to make the system more complex and unreliable. All for a gain of maybe 1-2 mpg.

So, concerns that I have are driveline wear, and increased drag. Drag isnt the biggest issue, I could live with slightly lower MPG. But if it caused significant loss of performance, then that could be an issue. Driveline wear is a biggy. Potentially you could have problems with the transfer case if the order of doing things is messed with. It is supposed to get the front shaft sped up, engaged, get the axles spinning, and THEN engage the hubs. So I don't know if this would cause problems or not.

So this is my idea. Anyone tried this, on purpose or by accident? Anyone who has not tried it but has some technical knowledge want to chime in?

Cheers! :beers:

Originally Posted by wildvodka (Post 4138852)

Hey all, I was following a thread on the IWE problems associated with leaking or otherwise malfunctioning vacuum system, and I had a question about a permanent fix.

Has anyone tried simply disabling the vacuum system entirely? You can block or plug the vacuum line at each IWE, which will permanently lock them.

So hear me out...
By locking the front hubs permanently you will cause them to always spin the front axles, and turn the front differential. However, unless the truck is actually in 4wd mode the front diff gets no power supplied to it, because the front driveshaft is not engaged by the transfer case. So, you will get increased drag, which may adversely affect MPG, and there is a slight possibility that you will lose some performance due to drag on the front wheels. However, I can't see that it would be that bad. Certainly it wouldn't be any worse that the pre 2004 models with 4wd, right? Because that is essentially how their systems operate.

My understanding is that the IWE are only there to decrease drag on the front drive train when in 2wd to increase fuel economy.

From reading the document on "principles of operation" for the Ford 4wd system, it seems to me that two things happen when switching to 4wd. First the transfer case shifts over to engage the front drive axle, while it does this it also uses a clutch to make the front drive axle match the speed of the rear drive axle. If the axle is already turning because the front hubs are locked, then this should be unchanged from standard.
Then it locks the front hubs using the IWE. Since they are already locked, this step is unnecessary. There would be no need to change any components, the vacuum system would still go through the steps to lock the IWE, just nothing would happen.

So what you would be left with is a system that only has the transfer case and its components as moving parts when switching to 4wd. No worries about water in the system, no problems with vacuum leaks.

It just seems to me the IWE system is superfluous, it serves no purpose other than to make the system more complex and unreliable. All for a gain of maybe 1-2 mpg.

So, concerns that I have are driveline wear, and increased drag. Drag isnt the biggest issue, I could live with slightly lower MPG. But if it caused significant loss of performance, then that could be an issue. Driveline wear is a biggy. Potentially you could have problems with the transfer case if the order of doing things is messed with. It is supposed to get the front shaft sped up, engaged, get the axles spinning, and THEN engage the hubs. So I don't know if this would cause problems or not.

So this is my idea. Anyone tried this, on purpose or by accident? Anyone who has not tried it but has some technical knowledge want to chime in?

Cheers! :beers:

Originally Posted by vigness (Post 5267285)

The front diff is limited slip. Being normally free spinning and never actually slipping, it is VERY limited slip. It's an easy part to replace. Wheel off, top ball joint, tie rod end, axle nut, and the three little 5/16" screws that hold it in place. Even hunting down my 21mm socket it only takes me an hour. I have an '05 and have replaced them twice. Always do both of them, and Rockauto has them reasonable, $50 to $75 each.