2002 LS Drivetrain noise

LS has 29,000 miles. I have two LS 2002 cars. One car has a drivetrain whining at around 64 MPH but has a lower level of whining at all other speeds. Repalced all four tires, had a four wheel alignment and all wheels balanced.
Any input on the cause would be appreciated

I'm late to the party but it's probably your rear drive axle's. Fords' fix is thicker axle shafts.