question... I believe that my actuator is shot, I tested this in theory on how it works, I simply took appart the hub so that I could see the actuator, and the engaging spline gear was just free moving, didn't feel any spring tension pushing is out, I then started the truck, and let vacuum suck it in, how ever, it was still free moving, with the truck still running, and then placed it in 4hi, and spline gear still moved freely, I think I have a hole in the diaphram on the actuator... solonoid is brand new... I tried using the 4wd to pull out a buddy yesterday, when I put it in, it sounded like it was binding, but when I was going straight, and now that i look at it, it just wasn't engaging all the way, so I'm assuming there is a spring in there that pushes the gear out, to engage when no vacuum is present, how ever, it was grinding, and binding, so I took it out, and was luckily able to pull him out with a long rope in 2wd, how ever, I think I had damaged the diaphram, because now it won't completely go into or out of 4wd, so kinda not drivable.... any input on this.. lemme know it would be greatly appreciated, thanks!

2006 f150 lariat 4x4 4dr

 

There is no spring. Its vacuum controlled. When the truck is running on each side there is a vacuum line running to the IWE Integrated wheel end. If they are working correctly with the truck running jack up the front end and spin the front wheel the CV axle shaft should not turn. If it does turn the actuator is leaking down. If its partially failing then it'll make a grinding down whilst driving down the road at different times. There is also a actuator that sits on the firewall passenger side right by the PCM, if that fails they won't engage correctly. There are a few check valves also that can be tested by taking them free and blowing through it. You shouldn't be able to blow through it, but should be able to suck through it. If I remember correctly both these check valves aren't to far from the actuator on the firewall. They will be little plastic white pieces that plug into the black vacuum lines.

When the truck is placed in 4X4 it should release vacuum pressure, and turn. If the truck isn't running and you attempt to test this theory it is of course going to turn the 4x4 because there is no vacuum.

This is the vacuum actuator on each wheel end. They are bolted right behind the wheel bearing. You do need to remove the cv axle to get it.

 

I understand how they work, as far at the vacuum goes, how ever, when releasing vacuum, what physically shifts it over to the gear in the hub... if there's not a spring to put it out, then how does it do it?

 

Could be the actuator itself on the truck. I believe its located near the transfer case... I however haven't heard many having issue with this. When my did this I had been driving it during the winter months with the windows up. It had been slowly grinding down the IWE to the point it wouldn't lock in to 4x4 correctly. Anytime I put it in 4x4 and put strain on it (trying to pull a ford T-Bird up hill that had frozen to the ground) it would make a terrible rack like that, and the 4x4 wasn't doing what it was suppose to.. I ended up replacing my IWE on that side, and it fixed the issue. The wheel bearing had a lot of ground up shavings also preventing things from locking in fully. I have a feeling that was part of why mine was slipping. So you may check that and make sure. If not then let me know what you find out there is an electronic part that actually actuates the 4x4, once its engaged.

Nothing but release of vacuum shifts it over at the hub. You mean what actually shifts the 4x4 to turn all that.

 

There is a spring that causes the IWE to engage (the default position without vacuum). Vacuum pulls the gear teeth out/away. I have a cut-away diagram I can email to you. I can't get it to load here or on my photobucket- it's a PDF.

You can remove the IWE without removing the CV shaft completely. Here's how, with tool list etc...the cut-away picture is in the thread somewhere I think. IWEs are about $80 apiece if you get them online.

http://www.f150online.com/forums/200...replacing.html