Put the truck in 4high and see if it continues to produces the sound, if it doesn't then its a vacuum leak to the transfer case not allowing it to engage or disengage

 

mine makes a squalling noise when i floor it from a dead stop. dealer said they could not get it to do it so ill have to ask them to look in to the vacuum lines.

thanks for the post on this!

 

Yeah, you're right. 03 Ford expo 5.4 EB. When accelerating hard or uphill around 2000 RPM noise would start, then stopped immediately once I left off accelerator. Popped it in 4H (immediately made same noise until engaged), no noise at same RPM's and conditions. I know this because mine has been doing for ssooooo long (a year) I could create the noise on demand. Do you know how much the vacuum leak cost to repair?

 

Did this fix your problem? Mine is the exact same and I was wonder cost/DYI possibilities.

 

Check some of the threads for IWE Solenoid. It seems to have been a common problem with and easy fix. In one of the threads someone posted a video he recorded while his truck was making the sound. In another thread there are some nice pictures of the old part and the new revised part.

 

The dealership covered it but I would assume it's as simple as replacing the vacuum line? It also turned out that the bearing was bad as well in the wheel caused by it not disengaging so I would check that as well

 

Yes replace or check your vacuum line to the transfer case and ensure that your wheelbearings is intact

 

My truck has been making a rattling noise when I press the gas but goes right away when I let off I replaced the vacuum hose to the brakes like the dealer said it is still doing it I can't figure out whats the cause but in no way does it effect the truck towards speed it's just a noise in the front left wheel well area

 

Welcome to the forum, East2k11. Did you return to the dealership for diagnosis since the noise came back? How many miles are on your rig currently?

Crystal

 

They said it could be the 4wd actuator but I wanted to see if anyone else was told that and I have 71,000 on it now

 

Thanks for responding, East2k11. If you'd like, I'd be happy to loop in your regional customer service manager. Since you're a new member, you may not have access to PMs yet. If that's the case, send an email to custserv@ford.com with your full name, best daytime phone number, VIN, current mileage, and servicing dealership. This email address isn't actively monitored, so be sure to put my name ("Crystal") in the subject line and post here once you've sent it. That's how I'll know to go and hunt down your message.

Crystal

 

have you inspected the check valve in that area as well? That is what was wrong with my truck all along. Sorry I didnt' update this thread, I started a new one explaining all of my symptoms and what fixed it.

The check valve is used to keep vacuum in the vacuum reservoir as well as keep vacuum to the IWE's (Integrated Wheel Ends) when vacuum drops off during acceleration. I thought mine was good when I first inspected it... when I sucked on one end or blew on the other it would seal...eventually. It took about a second to seal and took a good amount of pressure/ vacuum to do it. After buying a new one I could see the clear difference between the 2. the new one took no effort to seal vs the old one took quite a bit of press/vacuum to seal up. that is where the slow favuum leak was coming from allowing the iwe to start to engage when it wasnt' supposed to and produced the grinding noise.

Hope this helps,

Q.

 

Alright .....I just got done having this exact problem with my truck after getting a tune up and tension pulleys replaced. Started making a sound like flapping sheet metal in the wind.....or a tape measure stretched out and it collapses is the best description. Only happened between 50 and 60 mph. Turns out it was a vacuum hose that was cracked going to the front hub lockers. It was explained to me that it is normally under pressure to keep it from being locked. It is at most pressure at freeway speeds, so with it leaking, the lack of pressure is trying to engage the lockers for 4WD but not all the way.....so the sound I was hearing was the gears rubbing against each other......the tech and I only discovered it when we were travelling at freeway speeds and engaged the 4WD on the fly.....in 4WD, when accelerating 30 to 60.....the sound was gone......disengaged the 4WD and the sound returned. When back at ford, the vacuum hose they found that was the problem was located just by the corner nearest the passenger side firewall....on my 2008 firewall behind the battery. They replaced the vacuum line and it fixed the metal noise I was hearing. Hope that helps because I, all my friends, and almost everyone at ford was going crazy trying to figure it out.

 

Check my recent reply.....had a similar problem fixed today. Never would have guessed it was that.....even had techs at ford scratching their heads.

 

Ford TSB 14-0100 I do quality control at a Ford Dealership and what you describe sound like a transmission 5-3 down shift squawk from transmission. When I first heard the noise, I thought it may be exhaust, or a turbo. Turned out to be transmission