MikePDX

Gents,

Hi, I'm having a pretty strange issue with my 2006 F-150 FX4 (15k Miles) that I'd really like to get some opinions on. About 3 months ago I my truck made a quick grinding noise, followed by a light "Thump" or shudder as I was depressing the brakes and coming to a stop in town. While it was quick, it sounded like it originated at the front drivers side wheel and I assumed a small piece grit had gotten between the rotor and caliper and been ground up, end of story no big deal. It happened a few more times, several weeks apart, but it was quick and I always managed to come up with some logical reason it might have happened (e.g. the thump was from a 2x4 in the bed sliding, must have caught a pice of gravel in the caliper, etc...) until last week that is, when it happened 3 times over the course of my short drive to work, with nothing in the bed, and the grinding went on for several seconds - and definitely sounded metallic.

Detective time. Each time it made the noise I was stopping or just pulling away from a stop and the origin seemed to be my drivers side front tire so... I crawled under, looked for gouging on the rotor (nothing), a loose caliper (nope), something dropping down onto drive shaft?? (nada), huh??? Which then made me set out to see if I could find a way to MAKE it happen, and after trying everything I could think of, no luck. Just perfect, quiet, braking. And since it seemed mostly harmless and the truck was still under warranty, I decided to keep driving it and see if I couldn't isolate the problem further before taking it into the shop with the dreaded "Un-replaceable Mystery Noise" complaint. So, I drove it for a few more days and it would occasionally (apparently 100% randomly) make the noise. And then things got strange. On my way home from work later that week at about 35 mph, I heard a god awful metal on metal grinding noise, that telegraphed through the steering wheel and pulled the truck ever so slightly to the left, almost like I'd hit a shallow puddle of water (it was dry out . The grinding noise and pull lasted for about 10 seconds then abruptly stopped, without any action on my part (no thump this time). All of which made me call into my dealer to have them look at the truck ASAP, since it was happening while driving instead of just during stop and start. The quickest appointment they could make was a few days out and since I don't have another way of getting to work, I kept driving it (slowly on side roads) and it kept making noises at stop and start, still at random, but now with the fun addition of the occasional grinding while in motion and without fail, it happened EVERY TIME I DROVE THE TRUCK.

So, on the day of my appointment on my way to drop off the truck... no noises, no grinding, nothing (classic). Anyway, so I drop it off and tell the shop supervisor everything I've just said above and also ask to have the 15k service done at the same time - since it involves pulling all 4 tires, checking brakes and bearings for endplay, etc... so hopefully they'll find something right? Well, they didn't. Nothing is wrong with the truck that they can see and during the course of a 14 mile test drive, nothing happened. So I pick up the truck, drive home, and no noise.

Well, to wrap this LONG post up, in the 3 days I've had it back I've heard the noise once but, it was so quick I almost missed it, which tells me the issue isn't gone but, something has helped it a bit. The only other factor I can think of is that the weather has turned rainy (in fact they day I dropped it off at the dealer and it didn't make any noise was the first rain in a long time) and before when I was having the problem, it was dry. And finally just in case you're wondering I'm the first owner, don't off road, and it's never been in an accident. Any ideas or thoughts are VERY MUCH APPRECIATED as I'm 100% stumped.

Thanks,
Mike

wde3477

Welcome to the site!

Has anything been done toward inspecting the 4WD components? Shooting in the dark here, but it seems that just about every other conceivable thing has at least been given a first-pass look. Just wondering if the front-end isn't fully disengaged, or something equally weird.

Keep us updated - this has me stumped too at this point, and the eventual solution would be good to file for future reference.

MikePDX

Great minds think alike That was one of the first things that occurred to me after I took a look under the truck and couldn't find any visible problems on the calipers or rotors (well that and my bearings), but I had no idea how to trouble shoot the auto 4wd system other than seeing if it would still engage (and it does just fine, smooth as butter) but the more I think about it the more it seems like this is then next thing to explore. Also, it's worth noting that the problem has never surfaced while I'm 4WD but then again, I've only put it in 4 a couple of times since the problem started and only for a mile or two each time... Anyone out there familiar enough with the auto 4 system to give me a couple of ideas on how to trouble shoot it (or give me some ammo to get the dealer to do so?) or punch a hole in this theory?

Thanks All
Mike

PS - Just realized that this might also explain the occasional "Thump"...
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penchar

I had a very simialar problem with my 05 4x4, grinding in the front end once in a while and the first time i heard it was on light break application on the drivers side. I did the same thing stopped and looked under the truck for diffent things, but could not see anything. I took to my dealer, and it was a 4x4 vacuum switch that had failed, allowing the 4x4 to almost engage when it wanted to.

Hope this helps

BillR1212

I have a 4x2 06 5.4liter with the same issue. It has never happened while driving, only when I am applying light braking or at a stop while the truck is in drive. When I shift it to nuetral it goes away. Also happens on a slow left turn. I also experienced it about 10K into buying my truck but never brought it to the dealer. Now after 26K I am getting worried that they may not find the problem in time. I just brought it in to no eval. They said everything was fine. Moral of the story, its a 4x2 with the same issue, probably not a problem with 4 wheel drive.

nashtruck

I'm glad I remembered your post because the same thing happened to me today. Driving on the parkway at about 65 when I heard a loud grinding noise. The truck was driving fine, no idiot lights, I thought a bearing on the alternator or something went. As I slowed to pull over I felt a thunk and the noise stopped. I'm thinking its an automatic hub hanging up in one of the front wheels. Did you ever figure yours out?

maxsteel

05' 4x4, does the same thing. I have had it happen both in and out of 4wd. not on a regular bases though, not enough to nail it down.

Santana

I think you may have the same issue I just solved today. I was hearing a grinding noise when starting out in my '05 and I determined it was coming from the pass. side front wheel. After a week at the shop, they determined it was from water getting into the vacuum line that makes the actuator disengage from the hub. The grinding noise was the actuator tearing up the hub. It also would not go into 4WD. Apparently it is a problem with F-150's built prior to April 2006. There is a service bulletin out on it. The solution was a new wheel hub and actuator. Also a new vacuum switch is in order. Hope this helps. As luck would have it, my warranty expired on Dec 31.

ford4x4wifey

Hello, I am new to this site but I have been reading a lot today about the mystery grinding noise.
My 2004 Ford F150 with 78000 miles has started with this noise. It started last week at 45mph and when we stopped it went away. Two days later on the interstate it started to do it again at 75mph. It stopped when we pulled over with a thumping noise.
I talked to my dad (the mechanic) and he seems to believe it is the IWE solenoid.
Now my question is, were is it located and is this something we can do ourselves or should I just bring it to the dealer.
Any help would be appreciated.

rbailey3711

I have been having the same trouble with my '05 Supercrew. If you played with the 4wd switch, you could get it to stop. However, it would come back when the vehicle sat overnight.
Just received a call from my mechanic and it will be a $410 (P&L) replacement of the vacuum actuator in the right front hub. I'm assuming the vacuum switch is good since it has only affected the right front and not both hubs.
If there is a service bulletin, wouldn't that be covered regardless of warranty period?