Rear end makes rowing sound above 30 miles per hour also tjere is a leak of rear end grease on the left rear wheel.

IF you have rear wheel drive then check the u-joints for wear/loose. Check slip joint for wear . Check rear engine mount is in good condition. Check wheel balancing

Bad News, your rear end needs rebuilt.

Jack up rear end and spin the wheel with your hand. Check for any types of distortions in the tyre and replace if necessary.

Check tightness of wheel nuts.

Check operation of rear brake.

Check for free play in rear wheel bearing.

Check condition of drive shaft and coupling.

A bad rotor shouldn't make any sound unless the brakes are applied. If you hear a rubbing sound at 55-60 mph, I would look at the possibility that the bearings are going bad. Look for play in the front or rear wheels when the car is jacked up off the ground.

this is caused by worn ring and pinion gears, there is no fix except a rear end overhaul

HI gemeni756,

Get the wheel alignment done. That should fix the issue.

Thanks
Smith

5 hours sounds about right plus seals and grease

Check wheel balance,
check steering linkages for loosness - such as tie rod ends, steering rack linkages etc,
check driveline for worn/loose joints and bearings.

You say the rear wheel axles and bearings have been replaced, you mention nothing of the front wheels, you have the symptoms of a front wheel bearing being worn out, remove them and check for pitting in the bearing rollers or the bearing races, I am sure you will find a problem. Hope this helps solve your issue with the bearing noise.