You know, when you blow steadily, not toot? Or how about the tone that the extension ladder makes at 50 mph on your service van?
That's the noise my truck's making.
Is that the trans?

 

From the way you describe it, it kinda sounds like a wheel bearing to me?

 

In my experience yes. Thats what my last 60e did before it gave up. if it feels like its having a hard time shifting its definitely trans. I parked mine tried to start it again and wouldn't move.

 

Is it a whirring noise? If so it could be a bad carrier or pinion bearing also.......

 

Do you have the ladder in your truck

 

No problems with the trans' performance. Now that bearings were mentioned, I'm wondering about the driveshaft support bearing. I never heard one before until it locked and spun the rubber in my '73 C30. I'm not discounting wheel bearings, but I doubt it would be the fronts as smooth as they turn. It doesn't whir any more than the beer bottle noise, but I have heard rear ends make a similar noise.

 

Thats what the rear axle on my 89 sounds like. Constant and above 35 mph. It has been that way for about 8 years and 10,000 miles now. Hadn't got around to it yet.

 

I had a wheel bearing destroy itself on my last truck, didn't make any noises other than the rotor touching the pads when you would turn. There were metal shavings stuck to all the grease behind the hub, my truck had its own lathe. Is it engine rpm related or speed only?

 

sounds like a carrier bearing to me.

 

lol. I was wondering the same thing.