vibration

Have an odd vibration problem that's getting worse by the day. Started about 3 months ago. On the road, my 02 will start vibrating at exactly 66MPH. It gets at its worse at 70MPH, so bad things in the cab start rattling. It stops at 74MPH and doesn't reappear all the way up to 90 (fastest I take her on the highway).

The vibration doesn't seem to be from the front end, the wheel doesn't shimmy along with the rest of the truck.

The tires are new, the wheels have been balanced and checked, the alignment is fine far as I can tell. The issue started before the new tires, so it's not them.

Odd part: When it's vibrating, if I step on the gas, the vibration either quiets a lot or stops altogether. I let off the gas, it comes right back.

Seeing how I drive 140 miles on I-75 every weekend, and the speed limit is 70, this is driving me nuts.

Any ideas?

 

Hey Bubba, how the hell ya been!?!? Yeah I told the guys at Tire Kingdom (where I bought the tires) about the vibration and asked them to be super precise on the balance....young kid, eager to please, he spun them once, but the big weights on, then spun them again and put tiny weights on. Said they were as good as they could get, from watching the machine I have to agree. Tires are brand new and the vibration was there before they were put on, so not the tires.

Was afraid someone would say something about the driveline, cause how the hell do you balance a driveshaft! Tape pennies to it and take it on the highway until it stops? LOL

 

I did, and thanks! May take you up on that later today. Live in a new (to me) house built in the fifties and rewired by an idiot. All the hots and neutrals are backwards at the outlets, my UPS units are throwing a fit. Going to work on that before the truck today.