Whenever I drive at a cruising speed, and hit 55mph (give or take 2 or 3mph) I can hear a very distinct whining noise coming from somewhere in the car. I personally think it sounds like it's coming from the right front wheel, but someone else heard it and told me to check to see if my differential was empty. It wasn't- and apparantly I don't know WHERE the sound is coming form if I think it's in the front and someone else thinks it's in the back. The whining only occurs at that little 55mph speed with the gas pressed. When I go faster, slower, or release the gas pedal, the noise completely goes away. I was thinking bearing, but I inspected the bearing in the front two wheels just a few months ago, and the sound was present before that. Any ideas where I should start looking?

 

well check the rear, easiest to do, usualy the pininon bearing deflects under load... but you said if u go faster or slower it disapears... wheel bearing noise is usualy present at most speeds... another posibility could be the reaction planatery gear set in the tranny... did you change anything recently....ANYTHING...

 

I concur on wheel bearings - usually, they make a lot of racket regardless of speed. The big however is that I had an 88 bronco II that did a similar thing to what you explained. D@mnedest thing to find. I actually drove it about 10k miles while it made the whining sound and it was at a particular speed too. Part of the 10K miles was an 8k mile vacation trip from Michigan to the west coast and back. Anyway, I finally decided to pull the front wheel bearings apart again and sure enough on one side a bunch of the rollers in one bearing were pretty mangled. The interesting thing is that I had them apart before the noise started and the only thing I could figure was that I torqued them too tight when I re-assembled them.

Drive line/train whines tend to occur at a particular rpm, rather than a particular car speed - so, to rule that out take it out and run at 55 in two different gears or, look at the rpm you run normally at 55 when you hear the sound, then run it at that same rpm in a different gear. That may help to see where it's coming from too.

My hunch - wheel bearing, just 'cause the story sounds so similar to mine.
Good luck
L

 

The car barely ran when I got it.I just not got around to fixing the major stuff,but the problem has been around since I first got it,so I wouldn't know what did it. I'm notquite sure how to checkthe pinion. That's kindanew stuff to me.But yeah, its a speed thing and not RPM,because it does it in both D and OD. I can go in and check the wheel bearings tonight or something, but I've already done it a short time ago and I didn't see anything wrong. I might have missed something, but I don't know.