I drive a 2004 4x4 F150 Extended Cab. It runs great but lately while driving down the highway it makes a loud grinding noise coming from the driver side front. I will pull over and the noise continues. Then it makes a loud clunk like something engaged or like a gear shifts really hard. One time the noise shifted from the driver side to the passenger side. It acts like the 4wheel drive is trying to engage? Could this be the solenoid or the actuator?

Any ideas?

 

If you are hearing it on both sides its more than likely a vacuum leak somewhere in the lines or the vacuum resevoir. There are alot of problems with the actuators aswell but try putting a vacuum to the system and make sure it holds and the integrated wheel ends fully dissengage.

 

It sounds like you have a vacuum line or solenoid problem that you will want to address as soon as possible to prevent damage to your hub actuators. I had the same issue and it ended up being a relatively simple fix.

The best write up that I've seen is on the f150online website under Technical Articles. I believe it's called "Everything you want to know about the IWE system". It guides you through the steps to diagnose the problem. If you don't have time to address it immediately, first read about how to temporarily disconnect the vacuum which will keep your hubs engaged and prevent hub and actuator damage while you identify the problem.

 

Replace your IWE solenoid and check all Vac lines...sounds like your 4WD system is loosing air and trying to actuate

 

Thanks for the advice. I will let you know the outcome after trying these fixes.

 

I'd recommend checking your vacuum lines before replacing your solenoid. I replaced my solenoid first...turns out it was ok...could have saved a few bucks.

 

One other thing, two common locations where the lines break over time is where the line has sharp bends behind the vacuum reservoir and above the right front wheel well.

 

dang .... i usually hear that when i turn on the 4x4

 

A clunk that you hear when you turn on the 4wd is the transfer case engaging and that is normal. If an intermittent or persistent grinding sound is coming from your front hubs when you are not in 4wd, it means the actuators are trying to engage because there is a lack of vacuum pressure. When 4wd is switched on, the vacuum is released, allowing the actuator and hubs to engage.