I have 2011 F150 with 150000 miles on it, so there is a lot of wear on the vehicle. I just bought it 6 months ago so I'm not sure how well it was taken care of before. Anyway, a few weeks ago, after shifting from 2HI to 4 HI and back, there was a bad grinding noise coming from both front sides. We decided to replace the vacuum hubs, wheel hub bearings with speed sensors, and as one thing came to another we ended up also replacing the strut assemblies, upper control arms with ball joints, lower ball joints, sway bar links and inner and outer tie rods. Before going through all this, we replaced the check valve and the solenoid, but the problem stayed the same. Another thing that's new is the ABS connector because it threw a fault. After we got an alignment, the truck drove beautifully for a few miles before the grinding came back, but only on the driver's side. We then replaced the vacuum line. The test drive went well, but when I wanted to take it to work the next day, it started grinding from the driver's side again, after less than a mile. I don't have any more brain power in me after dealing with this for almost two months, so I'm wondering if anybody can give a suggestion as to what else could cause this that we haven't considered yet.

 

Maybe something in here might help:

https://www.f150online.com/forums/ar...then-some.html

 

I went through all of that twice. We replaced the line from intake to solenoid but that only decreased the problem, didn't solve it. We also just replaced the (already new) vacuum hub to make sure it's not that. It was just as difficult to get up the vacuum on this one as it was on the old one. The grinding is still there. I'm at my wits end and have no idea where to go from here. Could it be related to the CV axle?