I have had my 2002 SLE for a year. It had 100K on the clock when I bought it. Has 126K now. I have never been able to get the wheels balanced correctly. I have tried two sets of tires and done spin balancing and the road force balancing 3-4 times... all at great expense. All shocks and struts replaced. Front end inspected and OK.

I have had 44 cars since 1975, and NEVER had a wheel balancing problem... ever. The vibration comes mostly through the car, I feel it through the seat above 60 mph - and a bit through the steering wheel, but not much there. The road force balancing made a big difference, but it still vibrates. Even my wife'* Explorer rides like a Caddy at 80 mph. Why can't my Bonneville ?

I was wondering if the tire pressure senders inside the wheels might be to blame ? Has anyone ever taken them out and replaced them with regular valve stems and disabled the system ? Can that even be done ? I am going to ask my tire expert friend at a local Chev dealer where I had it road balanced. But I would like to know what you all think. Why are these cars so hard to get in balance ?

There are no tire pressure sensors in the wheels. Low pressure is detected by the wheel speed sensors which are in the hubs.

X2 - Also...does the vibration happen at 60mph when you put the car into neutral?

If you've ruled the tires and wheels out, then you need to concentrate on body mounting hardware, the engine, the transmission flywheel and the torque converter, the transmission output shaft, the propeller shaft, the rotors and the hubs.

Oh great. I'll try some of those things and report back. All I wanted was a simple answer. But that'* why I posted it. Thanks.

Let us know how the battle goes. Will be here to assist.

Problem solved... left half-shaft.

I worked on it with my buddy at the Chev dealership. We re-balanced the wheels on the road force balancer - 20% improvement. We tried a set of tires and wheels borrowed from a brand new Impalla with 7 miles on it - no improvement. The alignment was a bit off. fixed that - negligible improvement. While it was in the air I noticed the left half-shaft outer boot was throwing grease. We took it apart and most of the "perminant lubrication" was gone. One of the three slide-balls was destroyed and had reamed out its slide-slot, alowing the whole assembly to slop around. It was really reamed out badly.

Replaced the left half-shaft...100% solved the problem.

So, you guys are pretty smart. It was a process of elimination and a keen eye on an unlikely culprit.