MegatronF150

Help needed! Lately I have been experiencing a grinding noise after I start driving after a cold start. usually doesn't last long, maybe a couple hundred feet down my street. It seems to be coming from somewhere on the front end, like maybe a wheel well. But it is totally random and seems impossible to replicate.

So last week while running errands, i got back in my ruck, it was still warm. It did it again, for maybe 100 feet. I stopped got out and climbed under, nothing. It almost sounded as if I was dragging something, but again, I saw nothing out of the norm.

That brings me to today. While driving I went over a rough set of railroad tracks, and for the next quarter mile, I heard the grinding noise. It started off in what seemed like the passenger front wheel well, then it moved to driver front wheel well. But after I stopped accelerating it disappeared. I have checked everything I can think of, so any help is extremely appreciated.

It is a 2007 Screw Fx4 with 178k miles.

BadFish523

Have you checked the IWE system? Wheel bearings?

tareed94

Check your vacuum lines, sounds like you've got a leak somewhere which is causing it to lock your hubs.

PerryB

Agreed. The hubs are trying to engage due to a loss of vacuum. Usually it's the control solenoid, located behind the battery.

powerranger262

Next time it does it, flip it into 4wd. It should stop.
Then it's time to start investigating the 4wd system, like stated above.
Mine did the same thing, and it was my passenger side actuator.
Check the solenoid behind the battery, to see if it has a little hood over it. The old ones did not have it.
There is tons of info on these issues on this site, and everywhere else on the interwebz.

GreyGooseF150

I am running into the same issue. Grinding noise from passenger side. Replaced the IWE and the axle while I was there. Still grinding. I tried a vacuum test but wasnt sure if i did it right. I plugged the end going to the IWE and put a vacuum line tester on the one running to the solenoid. No suction at all. I assume its a vacuum/loss of suction issue. Mine is an ‘08 but my solenoid has the hood on it with FoMoCo stamps so i assume its OEM. Will i get a check engine light if I disconnect the solenoid and leave the hubs locked in?

mattd17

No, you won't get a CEL for disconnecting the solenoid. All this does is prevents vacuum from reaching the IWEs, so they remain locked to the hub. This will keep your front axles/diff turning while driving and used the T-case as the only "disconnect" from 4wd.

If you have a vacuum gauge and connect it to the tube on the solenoid, you should be roughly 20-21" at idle. If not, then test it on the inlet side of the solenoid, start working your way back towards the engine and see where you do/dont have vacuum. I like to test on the outlet side of the solenoid, as that will tell me what is being sent to both IWEs, and then troubleshoot fro there. This test needs to be performed with engine running, with truck in 2wd.

you possibly have a crack in the tube heading to the pass IWE. Or a plugged vent tube. Or a faulty seal on the IWE. The solenoid either works, or it doesn't. if it doesn't, then both IWEs will show the same symptoms.