So I've had this truck for about a month... drives beautiful, and everything so far works other then annoying rattle or something with the belt or pulley, maybe even alternator. It's 0F - 17F up here in Buffalo, so doing any type of work to change the belt or pulley just don't feel like at this point, next week in the 30's, so much better I'll try that.

However, few days ago; I noticed a high pitch whistle sort of thing .. I thought it was the radio because it went away after like 2 seconds. I thought to myself bad frequency on the radio, like AM stations sometimes get.

However this week, more and more... now I noticed that it happens for longer and louder. It happens on accelerate, slower or faster doesn't really matter. Usually at about 40 - 50MPH.. if I take the foot off the gas pedal, it slowly goes away. Sometimes I think its still around but you can faintly hear it at all times.

I've read that it could be a low fluid in AT, alternator going bad, water pump taking a dump. So I'm on here, hoping someone has a 2003 F150 that had similar problem and fixed it. I know Honda Civics when their tranny goes, it whistles.

Suggestions?

 

I had a similar thing happen to me and it turned out to be my a/c compressor.

 

Does the pitch change when you turn on the headlights...things that put a higher load on the alternator? Could be power steering pump. Suck out as much fluid as you can and put in some new stuff....maybe?

 

Yeah might have to try the power steering. It's strange; it was completely gone today. No sound but it's also 25F vs 15F outside.

I was thinking alternator, since my belt or pulley or pulley on the alternator sound bad on cold start. Something might of went out even more to make the noise. Donno.

If I'm correct; and I didn't drive that much when the noise was around and today I never got to that speed to see if it's still there; but the noise was there before at about 50mph before it jumped gear. I was hoping it wasn't the last gear or anything as some have had that noise on the tranny last gear

I've got the belt, pulley to replace and gonna go get alternator and tensioner in a few days. Then wait for warmer weather to replace and see how she does. Monday will also drive to work at 40, 50, and 60 to see if it shows up specially since it will be around 30s.

My thoughts also were I sprayed water in these temps to stop the slip sound in my belt which might of froze in another part and well with 15F out it didn't warm up at all.

I guess I only got a way is to test, replace the pulleys, belt and tensioner maybe even alternator since it sounds as bad as it is and then go see if it happens. Hopefully not the tranny making that noise

 

Hey Catbones, I have a 2001 and mine has been doing that for 10 years. Read an article years ago about it and they said that it is a combination of 3 things, temp,outside wind speed & RPM's. The fins on the alternator will create the whistling. Could be wrong but I would hate to see you chase it with parts. That gets expensive. Try it on a warmer day and see if it still does it.

 

Thanks for the tip; yup it's gone so you are right and all others. I might just replace the alternator anyways as I think it's what sounds awful on startup from cold and goes away. Never can go wrong with a new rebuilt alternator at like $70 but that's it though, already got a nice list of fluid changes that I'll do in warmer weather since you never know how the PO treated her.