Tires, bearings or?

I have a 2002 suburban . I have a humming noise coming from the rear . It starts at 45mph and then goes away at 47mph. I hear it again between 60-65 mph then goes away . This is a fauint sound . When pulling a trailer the sound is much more noticable and more constant from 55-64 mph . When I let off the gas the sound is still there and fades as the truck slows.

Am I dealing with a bad tire ( I plan to rotate them to see if that is the cause ) or a wheel or axle bearing ?

To note I replaced the front wheel hub/bearings just about a year ago .

I doubt it’s a tire, it sounds like a bearing making noise or the ring/pinion in the differential making noise.

Have you checked the fluid level in the rear end?

This sounds like bearings to me, too!

But if you have the time - swap the tires front to rear. If the noise doesn’t follow the tires, it’s not them!