My '03 Ram 1500 4x4 Laramie Quad Cab has a bad vibration starting at 65+ (mph).
It's definitely a "lower frequency" vibration similar to a tire out of balance as opposed to driveline which is a much higher frequency.
Rotated the tires - no change.
Rebalanced the tires- no change.
Replaced the tires with new Michelins - no change.
Replaced the wheels - no change.
If it's not the tires or wheels, then what else could be causing the bad vibes?

 

Bad bearing, bad u-joint, unbalance driveshaft, bad center support bearing, etc. Basically, anything that is turning while you are moving.

 

Also check for bent rims.

 

He replaced the rims as well.

Maybe slightly bent axle??

 

Google "Dodge Death Wobble." While your description doesn't "meet" the classic criteria, others' experience may help.

I know that I've been compiling suspension parts as part of replacing hubs, axle u-joints, ball joints, drag link, pitman arm, tie rod ends, track bar busings, steering damper, shocks, etc. I bought a 2006 4x4 2500 HD with all original steering/suspension. I figured I'm going to keep the truck and might as well make that part of the truck new. It's frustrating to have this kind of issue. Dodge as much as admitted the steering was poorly designed and put out a new steering linkage - for the Gen 3 Ram.

 

Not the driveline - since the rear differential gear ratio is 3.92, then it turns 3.92 times faster than the wheels. The vibration frequency corresponds with the tire/wheels - not the driveline.
New rear bearings (rear differential fully rebuilt - no change in vibration before or after).

 

Thanks, but you're right - doesn't meet the criteria. I only start to experience the vibration as slow as 65, and always at 70 or faster.
There is no definitive "feel" of the vibration in the steering wheel, and the vibration disappears when I reduce speed. (Remember the song "I can't drive - 55"? Well, it's a bit faster for me...)

 

Check runout on the rear axles.

 

try the brake rotors?

 

What was the fix to resolve this?