We've got a strange sound that we're trying to diagnose on our 2005 E350. When we accelerate to get up to speed quickly, we get a whirring sound that seems related to the rpms. It's not related to driving. This also happens without being in gear. The higher the rpms, the higher the pitch. When the rpms lower on the gear change, the pitch also lowers. The sound goes away under normal driving/accelerating. So, once we're up to speed, everything sounds fine.

With the doghouse off, it sounds as if the noise is coming from right of center (from facing forward inside the van perspective). It also seems to be coming from the plastic housing related to the manifold. But we could be off on exactly where the sound is coming from. (Diagnosed with a heater hose as a stethoscope.)

The noise itself almost sounds like a bathroom fan where the bearings are going. Sorry for the less-than-technical definition. Again, it's only heard under strong acceleration. The odometer is just under 100,000 miles.

Also, the engine light has been on a while. Not sure if it's related. The code scanner says P0446. I've looked around and think I know what needs to be done with that (we live in the country - lots of dust, mud, etc - so I'll be cleaning out the EVAP cannister).

Any suggestions?

I'll try to post an audio clip soon.

Thanks!

 

My Brother in laws truck has a noise kind of a tinny sound that shows up under (hard) acceleration in the upper rpms right before a shift. He has never done anything about it, but we are pretty sure it is the inspection plate on the tranny. I read on here at one time the plate is made of very thin sheet metal on the earlier trucks. He has a buddy that had the same sound on a F150 also. I think the fix for it was to remove it, test drive to see if the noise is gone. If it is make the plate out of thicker material, or put a slight bend in it.

 

Where is this transmission inspection plate located?

Also, listening to the noise again reminds me of someone ripping lumber with a skillsaw. Again, the pitch changes with the rpms.

I've got the audio... just need to find a place to upload to.

Thanks

 

Just went out and looked it is right behind the oil pan on the front bottom of the tranny, looks to to be 2 bolts holding it in place about 1/2" wrench. It may not be the problem but worth a try.

 

Any more thoughts?

 

I have nothing else. Maybe someone else will chime in. If you find the source post it. Good luck.

 

I'm going to chime in with a non-standard bit of information. A few years ago I had a vaguely similar situation that I tracked down to a broken weld an exhaust pipe support.

It was actually quite easy to fix, but there would have been no harm done if I had just left it alone.....

Maybe you could better define "hard acceleration"? I.e., Is it "hard" because you get on it quickly, or do you mean just any time you're around 3/4 throttle, like maybe going up a hill?

In the one case I guess there could be some engine/transmission movement, whereas otherwise maybe its just an accessory like alternator or power steering pump?

 

Thanks for your input guys. If I'm easy on the accelerator, I typically won't hear it. But when I'm trying to get up to speed faster, then it shows up. I'll try to isolate the noise again today. But as it stands, it seems to be coming from the top side of the engine, midway forward, and to the right, from inside the van perspective.

 

Like barebones said check the exauhst. I have a heat shield rattling on our Taurus driving my wife nuts, using a rubber mallet and tapping on the exuahst under the car I have found 2 loose heat sheilds. I used a hose clamp to fix one but the other is in a place I cant get to. Check all the heat sheilds.

 

I had the same supercharger whine on my 99 F350 V10. Turned out it was my idle pulley that sits on top of the motor. I had all sorts of horrible thoughts when I heard the high pitched whine. I raised the hood and had my wife throttle up the engine and thats were the whine was coming from. I sprayed some good old WD40 on it and it stopped. That was 3 months ago and it hasn't come back.

 

Replaced Idler Pulley. Solved. The bearings were going.

Thanks.

 

Glad to hear it was solved, the symptoms sure sounded like a loose heat shield on the exhaust.