Gears & Axles - humming from the rear end

Hey guys, pulled my car out of storage. I had NO issues before storage (deployed) but now above 30 MPH it starts to hum. Not constant but like a WOM WOM WOM and it increases in speed as I go faster. No rattling, clanking or popping just this annoying sound. I replaced the gearbox oil today with GM rear end oil with additive (G80) specific. Any idea's? I took off the wheels and rotors and examinded the axles. Zero play in them and the spin fine. I'm putting a INCON tti kit here in the next few weeks so all my funds are tied up in the 5.3 engine i'm building and all the bs parts. Any help is appreciate.

No one else is having issues like this?

check the gears in your rear end for missing teeth.

I would say carrier bearing. How did the tires look, chopped any?

Flat spots on tires from sitting if it not on blocks.

Might run it on stands to try and eliminate the tires.

Good call guys. I'll let you know what i find out.

Could also be axle bearings?