Help- Dealership can't fix it
 

So my truck is currently sitting at the dealership while they "try to find the problem". i have this wierd rattle from the front right wheel assembly or possibly the Cat. It sounds like dragging tin cans down the road but only under load. It is an intermittant noise that kind of cuts in and out while your driving. It is not present in 4wd but the dealership tested the iwe solenoid and says thats not the problem. I thought maybe the Catalytic converter with but they say no to that as well after they originally thought the same thing after driving it. i have an 05 fx4 with 70k miles on it by the way... anyone have any ideas?

Same problem here...cant find the problem
Always seems worse while accelerating

Exactly... it doesn't matter if i am cruising and come to a hill at 1500rpm or have it mashed at 4500 rpm the noise is there. It is not present at idle or while when you let off the gas and coast...

Had the EXACT same problem on mine. Went through hell for a year and 6 or 7 trips into the dealer. Finally, after chainging 10 different parts...solonoid, switches,..etc, it turned out to be a peice in the HUB. It was not letting the hub completly disengage and woud make a Horrible "tin can" noise. Especially on cruise control, and starting to go up a grade......as soon as I let off...and then got back into it....it would go away.

Took me forever to get it figured out and I have never heard antoher guy say anything about this. I cant belive I am not the only one!

The end fix was to completely replace the hub assembly. No problems since:beers:

Good Luck!

Wow! Mine did this too when it was new. I thought it was something in the exhaust. It seems to have fixed itself (at least I think it did...) but it sounds like the same problem and only when going up a pretty steep hill or towing a heavy trailer.

If the noise goes away when you switch into 4 hi, and stops at traffic lights (when the truck is not moving) then it is most likely your IWE solenoid.

If it was your cat, the noise would be there when ever the engine was running, whether it was moving or not.

The noise you hear is coming from the 4wd hub trying to engage during weak or partial vacuum. The weak vac is caused by a bad IWE soleniod bleeding off vacuum. When you switch into 4 hi, the iwe dumps vac and allows full engagement of the hubs and the noise goes away, going back to 2 hi the niose eventually returns when the vac bleeds off allowing the spring inside the hubs to try and engage and causing the noise you hear.

I went through the "fixed itself" thing a few times.....it will come back!
And the best part.......it will NEVER make the noise when you have a Ford Tech in the passenger seat:mad:

I dont remember the exact peice that was the problem....I just know he said it was best to replace the hub assembly because every time you hear that noise.....bad thing are happening inside the hub.

That is pretty much what the service tech said yesterday when i took him for a ride. He said that the noise was only during load and weak vaccum but not while in 4wd. He then tested and told me the iwe solenoid was not the problem. Sounds a little fishy to me. But i guess we'll see when i replace it anyways!... as soon as i can steal my truck back from them.

drive around with a video camera

It could be the IWE. The solenoid may be sending vacuum, but the IWE not using it. It will not always be the solenoid. If it was the solenoid, it would more than likely be both IWEs making noise, not just one side.

Another possibility is a bad hub, or diapragm in the hub. A bad hub will give you give you the exact same symptoms.

Kingfish, a bad iwe can cause just one hub to grind, wichever side has the stronger spring.

Would that be a problem that comes in and out while you're driving though? Like i said before, i only hear it during acceration and under load on a hill. I would think that if it was something in the hub and not a vacuum problem that it would be an all the time thing.

Make sure none of the head shields are rattling against anything. The noise that the hubs make when they go bad sounds like there are bearings rolling around in there screeching. I've had both of these problems. :lol:

The heat shields were the first thing i checked. and there is definately not any screeching going on. I've had bearing go out in other trucks and i know the sound and feel of that. This sounds like throwing a tin can down the road every time you step on the gas or hit the slightest hill. There is no different feel or pull in the front when it makes the noise. That is why i thought a piece broke off and was rattling in the cat. during load and accel.

It's hard to describe the noise that the hubs make, but I'm willing to bet that it's your hubs are bad.