My 2004 F150 is making the same noise from the front end you hear about commonly. I have changed the solenoid on the firewall. Didn't help at all. I have good vacuum at the back of the hub so I don't think a leak is the problem. Does anyone know how much vacuum there is supposed to be? Can the problem still be the actuator? Is there an actuator for both sides? Please help if you have any suggestions. Thanks!!!

 

There could be one of several things going on here. First, to answer your questions.

If i remember correctly the service manual says you need about 20" hg (inches of Mercury) vacuum to ensure good IWE (Integrated Wheel End) actuation. There is a vacuum-actuated IWE at each front hub and this is what engages or disengages the half-axles from the wheel.

Both of these IWE's are attached to the same common vacuum line so if one leaks, vacuum drops across the entire line (downstream from the check valve anyway) and so you'll end up getting noise at both hubs; making it difficult to diagnose which one is bad on the fly. Also any cracks in the vacuum line can cause issues obviously and if you have a leveling kit these lines can sometimes be stressed in off-road (high suspension travel) conditions.

You say you have good vacuum at the hubs; I'm assuming you checked this with the vehicle idling and sitting still. One thing to remember is that as you get on the throttle and engine load increases, vacuum drops. So if you have a small leak you may not notice until the engine vacuum drops under load. You can check this by letting off the throttle when you hear the grinding noise and listening for it to disappear.

So, bottom line; check each IWE for vacuum leak separately and inspect your vacuum lines upstream and downstream of the check valve. Hope this helps and good luck!

 

Ive had a 4x4 problem when my leveling kit was installed a vacumm line came unplug and you could hear a whining sound when switching to 4x4

 

Thanks yes this helps. Yes when I let off the noise goes away. I pulled vacuum at the hub and it was pulling 15 I think. When I am in a lug like and get down on it is when I here the noise. Thanks very much.

 

I don't have a lift on it, it's just factory. Although I had a leaky battery which messed up some vac lines. Got them fixed but I may need to just go ahead and put new all the way.

 

Try this link out.

http://www.ford-trucks.com/forums/836438-everything-you-wanted-to-know-about-the-iwe-system-and-then-some.html


Hope this helps.

 

Thanks GregC

 

Just wanted to say thank you again GregC. I went and purchased a vac pump and found my problem. It was a bad vac line. No more noise!! YAYYYYY!!!!!

 

Good for you! Glad the info helped.