1999 chevrolet silverado 1500 4.3L long box

check fluid in front diff. the check the wheel bearings

Wheel bearing on the right front

check for an exhaust leak or something loose onthe exhaust heat changes these things alot check it cold

I would check for a bad wheel bearing on the rear, also check the u-joints on the drive shaft.

The ticking/buzzing noise is a common problem on the RX330. There is a plastic pin that is attached to the instument panel which inserts into a plastic housing on the firewall. This holds it in place to the firewall. It is a design problem that model year. In the 2006-models on have a piece of felt covering the plastic pin to reduce the vibration noise. The same noise can occur on the passenger side behind the glove box. You can try to access the white pin and stuff some felt/cloth, but it is difficult with out dissassembling the dash or glovebox.

A exhaust heat sheild can make that noise

I think your right that its a bad bearing or hub. If your feeling it in the gas pedal and the floor, its most likely the front. If you can find an empty parking lot, try to get up to the speed it starts making the noise, and turn left and right. With the extra load being put on each bearing from turning, that will tell you which side it is.

Have you checked the u-joint yet? i had what sounds like a similar problem to yours and thats what took care of it for me...

A foreign object may have gotten into the fan blower wheel and damaged it which will make it off balance and produce a vibration.

There is an ABS fuse under the hood that you can take out, and the noise will quit. The noise is accually your ABS pump. They are kind of expensive.