Help with a weird noise!

[rprhyno]

I've got a 2005 F-150, 5.4 with auto and 4wd and about 31,500 miles on it with good regular maintenance. A new noise has started to appear from somewhere up front and seems to be happening more frequently. Basically it sounds like the sound a bearing makes that's going bad and spun at high speed - sort of a whine/howl and is pretty loud. You can also feel a minor vibration with the sound. At first I thought it was a fan clutch, fan belt or idler going bad, but the belt doesn't look worn or loose. It doesn't seem to be speed or accelleration related as far as when it occurs, but it does seem to drop in pitch as I stop the truck and ends with a solid "thunk" at slow speed that feels like it's coming thru the motor/trans mounts. I've tried to surge the motor and also shifted the trans into neutral to see if the sound alters with no difference - it only seems to be effected by decreasing actual vehicle speed. Funny thing is it never gets higher than a certain pitch no matter how fast I'm going when it starts and I've had it make the sound at 45-50mph and as slow as parking lot speed. I can never get a look under the hood when it's making the sound - before I stop it gives that thunk and the sound goes away. I'm thinking maybe transfer case trying to engage itself or shift itself - hubs maybe? It's happened about 8 or 9 times now and that thunk at the end has me concerned. I'm laid off right now and have to watch the $$$ and don't want to break anything really expensive! I'm a pretty good wrench and can fix most things if I can nail down the problem - any help? Thanks in advance!

[bridge]

Perhaps the hubs engaging? I know these trucks will engage the hubs when they loose vacuum in the IWE lines. Maybe you've got a solenoid issue or bad vacuum line between the solenoid and the hub? I think you should be able to pull the line at the hub while at idle in 2H and feel some vacuum.

[rprhyno]

Thanks for pointing me to the IWE solenoid - I did a search and the posts concerning the IWE solenoid acting up seem to match exactly what I was experiencing with my truck. I picked up the new part mentioned in TSB 06-8-15 ($24.95 at dealership) and did a vacuum test on the lines from the solenoid end. My lines are dry and the vacuum test showed no significant vacuum leakdown over 10-15 minutes, so the lines seem to be o.k. and the hubs were engaging correctly (locked with no vacuum, free during the vacuum test). I can't say enough good things about the information I've found here! I really liked the tip I found noting that the front drive shaft will be free to turn with vacuum applied in 2wd mode since the hubs and the transfer case will both be disconnected. It was a quick way to make sure the hubs were operating and that I was vacuum testing the correct line. Gotta love a quick and cheap fix!

[rmartens24]

You might want to do a search for the thread on alternators. Many people have had a bad alternator with a whining or squealing noise, including myself.

[nsaikia]

I had a whinning noise issue and it turned out to be the idler pulley bearings. Replaced it and everything is good.

[rprhyno]

Thanks for the further posts, but the IWE solenoid has fixed the problem. The sound I was hearing was similar to the sound of a bad bearing but more pronounced and you could feel it as well. Not to mention the fact that I couldn't change the nature of the sound by revving the engine. A bearing in the belt/accessory system wouldn't make the solid physical thunk with accompanying cessation of the sound as the vehicle slowed to below 5-10 mph or so. It was definitely related to something in the drive line and actual vehicle motion. The IWE solenoid issue was a perfect fit. The whine/howl sound was the moving wheel/hubs trying to engage without the axleshaft in motion and the thunk was the hubs engaging when wheel speed slowed enough to allow the hubs to mesh in with a resounding thud. That's also why I could never replicate or observe this with the vehicle stopped or parked. One tip I would pass along to anyone else trying to diagnose this - use a vaccum guage (like from a 1 man brake bleeder kit) and plug it into the lower vaccum line that plugs into the IWE solenoid (I think it was the lower line - upper line was vacuum supply from the engine. It's either one or the other!). Pump up the vacuum and see if it bleeds down. If the problem is a bad vacuum line then you can quickly see if you need to bother tracing them or not. If the vacuum stays solid then the lines should be o.k. and you can avoid wasting your time looking for a break that isn't there. You can also verify that you're sucking on the right line by reaching under and seeing if the front drive shaft turns. Vacuum applied to the hubs with the dash switch in 2hi will allow the shaft to turn freely. No vacuum and the hubs engage and lock the shaft.

[delta767]

i have the same noise seems like tc wants to engage at any speed 10 to 70 mph brought to dealer several times they cant reproduce sound so cant fix the problem now that i've read some these posts im copying some articles and bringing to my ford man to see if they agree thanks again learn something new everyday

[rprhyno]

Delta 767 - follow up on this pretty quick if it is the IWE solenoid - if that's the problem then the more it acts up the more damage the hubs will be taking. If it goes on too long you'll be looking at replacing the hubs! If it's like my problem, the trans case isn't the culprit, it's the hubs trying to lock in without the front shaft spinning at speed. The trans case disconnects the front shaft in 2wd mode so it's not turning the front driveline and when the hubs loose vacuum from the IWE solenoid then they try to engage. My lines and seals were good, but the solenoid itself was acting up causing loss of the vacuum signal to the hubs. Since the default no vacuum disposition of the hubs is locked, they would try to engage. The hubs also lock when the engine is shut off, by the way. The only way they unlock is when vacuum is applied to the hub mechanism.

[delta767]

thank you again RPRHYNO taking to ford tuesday call them my ford man in service is ordering the part infact he had another person having the same problem his truck willl be in there today we willl see what happens again thank you for the info
delta767

[thehost]

I Have the same sound in my front passanger hub. When I lock i the 4x4 it stops nut it only on one side. we have determined that the hub is not fully disengaging. Could it still be the IWE?

[delta767]

mine is the drivers side thats where my noise comes from its at ford now im having them put a new IWE solenoid on it under warrwnty now another problem is cv boot drivers side is leaking havent heard from ford yet ford will only look into to it if they can hear the noise so maybe bring them TSB to them about the bad IWE solenoid the TSB is TSB 06-8-15 show this to dealer see what happpens or put one in yourself FYI FORD just called me now as im writing this my left hub was destroyed gears and all in hub so im getting 2 new hubs and the IWE all under warranty the ford guy told me as he drove the truck to work to service it the noise came and he couldnt belive how loud it is he said i had no vaccum to that hub at all hope this helps

[thehost]

Well Its at Ford today. I printed out the entire Thread for them. We will see.
Thankfully the noise was happening at the same time. Oh yea Get this, They said that they have never heard of this problem. Yea RIGHT!

[delta767]

yeah i heard that before cant hear the noise ford will try to screw you but my ford guy heard the noise and is replacing both hubs and the IWE solenoid i tell you the ford dealer i bought the truck from said thay never heard of this so i will never bring my ford to serramonte ford ever again

[Roller150]

I just replaced my IWE solenoid yesterday and fixed the problem