I have been experiencing intermittent grinding noise/vibration from my truck that I first thought was something to do with the braking system. I first noticed it more than a year ago but the problem went away from a bit and only came back intermittently. Lately it has happened more often. From my research, the culprit seems to be the IWE system and a check valve replacement is probably the easiest/cheapest fix unless damage has been done to other parts. Anyone has experienced similar problem with their 4x4 F-150?