My car is rumbling with this bassy du-du-du-du-du that follows the car speed, not RPM and exists when coasting in neutral also. I don't think its the transmission. The steering wheel also starts to shake in the 60s and gets unbearable at around >75MPH. I ruled out unbalanced wheel(s), so lets assume its not that. I don't think the rumbling gets any worse when turning, so I don't think it's the CV joints - but this is just my speculation. Could it be the wheel bearings, or drive shaft or anything else? The car has 160,000 miles on it with no previous work on any suspension or drive/transmission elements. I would appreciate your opinions.

I don't know why your dismissing wheel balance so quickly. That's where you need to concentrate. It's either wheel balance or a bad tire or wheel but they would show up when balancing if the tech bothers to look.




78 Corvette Pace Car For Sale-18k mi orig-Florida

I have dismissed unbalanced wheel because steering shakes even at 80mph, which is usually well outside the natural resonance of the suspension. It is erratic too, sometimes I can drive 75mph with very little shake - an unbalanced wheel would always shake the steering. I did have an unbalanced wheel (it was actually bent and I had to replace it) a few years ago on this car, and shaking was evident really only around 55-60mph and now it doesn't feel like that.

Balance your wheels and inspect the tires at the same time.




78 Corvette Pace Car For Sale-18k mi orig-Florida

I took it to a garage, CV joint boot is gone but the wheels were in balance.

The c/v boot isn't going to give you a shimmy at 75MPH but the tires will.




78 Corvette Pace Car For Sale-18k mi orig-Florida

Let me soak this in, for just a minute....You are driving a vehicle with 160,000 miles on it, with a known problem, at 75 and 80 mph? Do you even care about others? Could be wrong, but don't know of anywhere in the U.S. that has a speed limit above 70mph.
Loren
SW WA

And we SHARE the roads with these people! Egad!

T
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Tom Greenleaf - MetroWest, Boston

If you get the front end up off the ground, can you "wiggle" the front wheels if you pull and push on them? Could be bearings or hub bearing assembly??

Just my two cents of course

Your 2 cents is as good as anyone's. I think we have a whole dollar now - laugh,

T
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Tom Greenleaf - MetroWest, Boston