high pitched whine

[Drth Vdr]

Hi all, hope someone can chime in with some experience. My wife (who is the primary driver of our Expy) just called and told me that there is a new sound coming from the car (never a good phone call to get).

It is a high-pitched whine (similar in tone to a fire engine siren based on her description). It gets higher pitched when going faster, and lower-pitched when going slower. It does not make a sound when stopped and idling, even in gear.

Any thoughts?

Thanks!

 

[spotdog14]

Does it shake at all while its happening, also does it only do it while it is cold?

 

[Drth Vdr]

Thanks for your response,

No shake, yes only when it's cold. Actually, my wife just called back and said it stopped after about 10 minutes of running. It was a cold night here, but it was parked in the garage - figure 40 degrees or so in the garage.

 

[spotdog14]

Thanks for your response,

No shake, yes only when it's cold. Actually, my wife just called back and said it stopped after about 10 minutes of running. It was a cold night here, but it was parked in the garage - figure 40 degrees or so in the garage.

Its probably everything just warming up. I had a 2002 Explorer that had a bad rear differential and that thing whined like no other at highway speed. I think its just either the engine or the drive train warming up, the engine always rev's higher too when its cold.

 

[Drth Vdr]

I guess what concerned me (and I still haven't heard this noise, mind you) was that it got higher pitched with car speed, not engine speed. I immediately thought of wheel bearings, but she said it didn't get louder with turning... I appreciate your response.

 

[Stoned06]

It might be the start of a wheel bearing going bad. The colder night firmed up the bearing grease and exaggerated the noise. Could also be the rear diff oil was thicker too. Just keep an ear out for the noise when warmed up though. I would expect it to slowly get worse if it's either a bearing or diff.

 

[eddiemoney]

I have had an off/on whine that shows up at highway speeds.....been going on for 35K miles intermittently....still can't find why and doesn't get worse like a bearing - i have given up

 

[Captain Morgan]

Yeah we're gonna see a lot of this as the temp dips across the nation. Idler pulleys, A\C clutch bearings etc etc.

With the truck in park, idle it up and see if it is related to RPM, engine temp, is it under the hood at all, or from underneath? You may have to check it again from a dead cold start.


.

 

[mindgame]

I agree with Stoned06, sounds like the start of rear diff bearings...