I have an 05 5.4 xlt and when the truck is under load its starts making a rattle noise in the front end but when i turn on the 4x4 it doesnt do it anymore.

I dont know if this makes a difference or not but it was an arizona truck that never had the 4x4 used. Any insight would be greatly apprieciated. thanks in advance

 

I am having the same problem with my 5.4L FX4. At first it sounded like a heat shield but I don't think that's it. If it changes with load and 4x4 status, it might be something related to the engine or trans mounts?

 

It sounds like you have a bad iwe actuator or iwe solenoid.

 

Jack up the front and start the truck and spin the front wheels and see if the shaft turns. In two wheel drive and the truck running the shafts should not turn.

 

I think it may be related to the bottom of your front shocks. When in 4x4, the front end pulls putting more stress on the shock. Your bushing may be worn or a shim would fix the problem.

 

I think it's a Actuator rattling. Under load the vacuum drops and if your solenoid isn't working prop or the check Valves are faulty the IWE's will leak down and start to rattle

 

thanks guys! when i get around to it ill check out these possible causes and let ya guys know!

 

Best way is find a vaccume pump with gauge and test it that way so you can see if the check cables are working and the seal on the IWE is holding