Okay so here is the problem. When I am driving down the road (could be 15 mph or 65 mph) I get a grinding noise out of my truck. Truck is a 2004 F-150 FX4. First time it happened I pulled over to check to make sure I wasn't dragging anything and I wasn't. I didnt think much of it bacuse it was dark and figured I ran over something. It didn't happen again for another month or so and now it is happening on a weekly basis. Sometime's it will happen for just a second and sometime it will not stop till I slow down to about 5 mph and then there is a grip thump noise. Also I can make the noise stop it stop by switching into 4x4. It never happens in 4x4 alone. I read about it and thought it was the switch for the transfer case so I took it in to have it worked on. The shop came back and said it was the transfer case motor and replaced that. I drove it the next day and it is still making the noise. Again this happens maybe once a week and I can never anticipate it happening. The transmission works great. I love this truck and besides this it is perfect for me. PLEASE HELP!!!!!!!!!!

 

I have the same problem on a 2008 F150. I am fairly mechanical but somewhat automotively challenged, but it seems to me because the trouble is so random, that possibly there is a computer glitch telling it engage something, and then when I slow down there is a thump and the grinding quits. I also cannot do anything to make it happen-it only does it at random times. I'm taking mine is to have it checked by a Ford dealer (under warranty). I'll mention your experience to the service mgr and respond again here with anything I find out.

 

QWERTY1500,
Thanks so much for the fast reply. If you could please let me know it would be great. My next option it to take it to the dealership so it would be nice to know what they said about yours.

 

I found a bunch more compliants like ours...check out "mystery grinding noise" in this forum. Sounds like a vacuum switch might be a problem

 

It is probably the vacuum actuators. or some vacuum issue related to the actuators

 

I have this same problem in my 09 fx4. Did you ever figure out the problem? I'm getting ready to rebuild the transfer case.

 

Check out this thread, doesn't only apply to 12th and 13th gens. Might help you guys out.
https://www.f150forum.com/f2/4x4-iwe...g-cure-404406/