Loud strange, obnoxious grinding noise

[ediddily]

I have 07 XLT 4WD, when driving in 2WD on a curvy road, I get this loud scraping sound coming front the Left Front wheel area. It sounds like metal on metal, but I dont really know.
The strange thing is when I switch to Auto 4WD, it magically goes away.
So I think it has to do with the 4WD obviously, but not exactly what. Any suggestions or thought on what it may be?

 

[FordandPolaris]

I would say it is a wheel hub going bad. Does it feel like it is dragging on that side? In other words does it pull to the left while driving straight? It could also be a dragging caliper.

 

[mindgame]

+1 on hub actuator..

 

[ediddily]

no, no dragging. how far in is this hub actuator? This is my 1st 4WD car.

 

[thegeneral]

food for thought-

I have an 08 XLT 4wd. Same noise on curvy roads, usually during a downshift. and usually while on an incline.

I thought hub, trans as well until the other day. It made the exact same noise directly after starting it, in park. I'm sort of leaning towards loose heat shield at this point? Or air conditioning compressor engaging.

The noise happening while in park gave me a sigh of relief!

Listen for it next time you start your truck...

 

[mindgame]

no, no dragging. how far in is this hub actuator? This is my 1st 4WD car.

The locking hub actuator is the circular thing that is currently covered with metal tape in my pic. There are 2 hoses attached to them up on top. (I have temporarily removed my half shafts for the moment)...

The actuators works like this..
If a vacuum is present, it pulls the gears away and 4x4 is disengaged.
If there is no vacuum, the gears are engaged for 4x4.

Therefore.. You will need to do some troubleshooting... All you need is a vacuum pump/gauge.. Attach pump to the larger of the vaccum inlet, and pump to around -20psi. if the vacuum holds, then the actuator is good. If not, then it needs replacing.

If your actuator is good, you will then need to move higher up the chain.. and test the vaccum hoses..
To test the hoses, you will need to locate the IWE solenoid on the firewall passenger side. Put your pump in the larger tube, and test vaccum. IF there is a leak, replace tube assembly. If not, replace the IWE solenoid ($30).. Replacing this is a common issue also..

Actually.. If you are willing to just spend around 30-40, you can just replace the IWE solenoid.. No need to get dirty... Most of the times, this fails first anyways.. Causing the problem you just discribed...

Good luck