Remember, your front differential is open. You may very well get one wheel spinning. With the truck running in 4 Hi with the truck in neutral, try spinning each front wheel. Does the half shaft spin with it?

 

I'll try when I get home today.

 

With the truck off/running and in 2wd/4wd and in neutral/park the pass wheel spins with the h/s and the drivers does not. But when I had it up on blocks the other day with it in drive the drivers h/s spins in drive but the tire does not nor does any of the pass.

I've got some new vacuum lines to replace all of the old plastic crap but not sure what the vent line is connected to. I know the vacuum goes in but is it some sort of check valve as well?

 

Remember, the way the system works is that you need vacuum to release the IWEs and half shafts. Lack of vacuum and or shutting the truck off causes the IWEs to lock. Think of it as a "normally locked" system - which is probably good since loosing vacuum will actually give you 4 wheel drive.

 

So I'm guessing mine doesn't work then since in 4wd the tires spin and with the vehicle off they spin.

 

"Doesn't work" is kind of a wide category. There are several parts of your 4Wheel Drive system that might not be working. First, your ESOF motor might not be shifting your transfer case. You would know if that was the problem if the 4Hi and 4Lo lights didn't come on in your dashboard. This would prevent you from sending power from the TC to the front differential and front wheels. Are you getting the lights here?

Second, you could have the TC shifting correctly and sending power to the differential, but then only driving one (or neither) front wheel. The cause here would be one or both IWEs not locking or unlocking. (And remember, they're normally locked.) The root cause here could be a bad IWE Solenoid up on the firewall, leaking vacuum lines and / or bad check valves. In this case, you'd have an indicator light on the dash, but no power going to the front wheels.

 

I get a lot of email requests for the repair documents, so as a reminder, the links to all the documents are on page 1, post 1 and 6. I figured out today why this was so confusing for people. The thread was copied to the Articles-How-To section and left in the 2004-2008 section. This is good because this same system is still in use on current models so the How-To section gets a wider audience. BUT they are both still active threads and emails are coming from both threads. So upon looking today, I found the thread that had been copied to the How-to section didn't have the links to the files on the first post like the original. So I have updated that post to be exactly the same as the original post. All file links are shown, as I mentioned above, on the first page and in post 1 and 6.

I hope that helps folks find them easier.

 

I have an 08 f150. I replaced the solinoid once 2 years ago. Seems like my problem is back.

Has anyone else had to do these repairs on a 08?

 

No doubt there has been. It's the same system. As far as I know, up to the current model year.

 

From what I have read on this website, I have a vacuum leak.

Time to find it.

 

I need a new vacuum line for my drivers wheel. What is the part number?

 

You can buy vacuum line by the foot at your local parts store.

 

About a year ago I replaced the IWE shaft on the passenger side and that fixed the problem. Now the passenger side is acting up again. Vacuum checks out fine so it is either the shaft again or possibly the actuator. Is there any way to test the actuator? Thanks!

 

Symptom Question: I had been experiencing the failed solenoid symptoms of the 4WD trying to engage on it's own... My mechanic cleaned/flushed out the moisture to see if that would resolves things - for the time being anyway. So far so good.

Here is my question : I am also experiencing a low growl sound at times when slowing. Most noticeable below 30mph. Not always and sometimes more noticeable than other times. Almost sounds like new or poorly worn tires on the road - that kind of sound. Thing is, I can even hear it on my dirt road sometimes. Tires wouldn't make that sound on a dirt road... Could it be damaged IWE actuators?

 

The part number for the WHOLE vacuum hose kit is 7L3Z-7A785-A

What is the part number for just the hose that connects to the actuator?
3a788?