In what should come as no surprise to anyone is that a 2011 F150 with 174,000 miles has its fair share of problems, one of the most egregious for our 2011 F150 XL Project Truck was a broken IWE system that caused pretty horrendous grinding and sounds of suffering when first taking off and when turning.
For the uninitiated, Ford's Integrated Wheel End (IWE) system is what locks and unlocks the front hubs when you change back and forth from 2WD and 4WD. The system works off of vacuum and functions a little counter-intuitively in that it uses vacuum to keep the hubs unlocked for 2WD and shuts off the vacuum to lock the front hubs for 4WD. While actually a pretty clever way of doing things, anything vacuum-operated is prone to problems, and the IWE system isn't an uncommon point of issues on any 4WD F150, regardless of engine option. The IWE system is made up of four basic parts: 1). The IWE Solenoid/Valve Assembly (part# 7L1Z-9H465-B), which controls the flow of vacuum when you change drives. 2). The IWE actuators (I used Dorman's kit for this guide, OEM part# is 7L1Z3C247A, I believe). 3). The IWE Vacuum Line (part# BL3Z-7A785-A). 4). Your front wheel hubs (I used Moog part# 515119), though not technically part of the IWE system, they play a role and can suffer during an IWE failure.
Which brings us to our 174,000 mile XL, which did spend most of its life working outdoors. When the IWE system starts to fail, the first tell-tale sign is a grinding sound in 2WD, usually only under certain conditions when it first starts, but gets progressively worse as you go along. The grinding is generally caused by the actuators not getting enough vacuum to disengage completely with the hub, and while that sounds simple, there could be several causes. With the truck grinding pretty consistently under part throttle and while turning in 2WD (but not 4WD), I knew something was up with the IWEs. Not knowing how long it had been doing that, I assumed that both the actuators and the hubs were toast, which turned out to be a pretty good assumption.
While the straight-line grinding was pretty much taken care of, the truck was still grinding when turning. My next step was replacing the IWE solenoid, though knowing what I know now, I wouldn't have bothered, since it was adequately allowing vacuum through. Still, it was an inexpensive part and easily accessible, so what the hell, it might work.
However, the real problem was this:
That's the driver's side IWE actuator vacuum line with a nice tear in it near the push clip that holds it to the frame near the ABS line. It was almost impossible to see, since it was on the side facing toward the frame, but with the IWE line being that only remaining culprit, I replaced it. In all honestly, this was probably the beginning of this truck's IWE problems, but given that it's a work truck and the IWE system isn't easy to diagnose, it probably went for awhile without anyone really caring.
Anyway, the moral of the story is that if you're getting intermittent grinding from your IWE system, check your lines first so that a $30 part doesn't turn into a couple hundred bucks worth of hubs and IWE actuators.
One other quick note: the Moog 515119 hubs that I used DID NOT have the correct connector for my truck's ABS body harness. I had to swap over my stock ABS wiring in order to get it to fit. I'm not sure if there's a model year or submodel split, but make sure you check before reassembling your hub and and knuckles.If all else fails and you're desperate to make the grinding stop, check out RCV's IWE Eliminators, which delete your truck's IWE actuators and permanently lock your CVs to the front hubs. While this generally results in a decrease in fuel economy and some extra wear and tear on the front driveline (though not by a significant amount), at least your grinding will be gone.