Hey all,

I'm currently driving a 2012 F150 4x4 Off Road with the 5.0 V8. This morning while I was driving into work I noticed a grinding or deep whining noise when I would let off the accelerator while in 4x4 auto. I switched to 2x4 and the noise went away. I also tested 4x4H and the noise was back again. The noise goes away as soon as I touch the throttle. Any ideas what could be causing this?

 

IWE's (kind of like front locking hubs) are not fully engaging. Probably a vacuum leak. Get it fixed before you totally grind up the IWEs.

 

Thanks for the reply 2stroked. From what I've read on this and other forums, it seems a vacuum leak would cause the grinding in 2x4. I will definitely take a look at that though.