Humbin coming from rear end?

just about a month ago my car started to make a humbing noise when i am on teh gas pedal and the noise gets higher pitched witht eh rpms adn is the highest in 5th gear, im pretty sure its not a wheel bearing becuase it only does it when im on the gas. i was wonderign if it was the rear diff fluid running low or my rear diff all together, any help would be greatly appreciated.

if you installed subframe spacers you will also get a humming sound when you are on the gas.

id say its a diff. the bearings start to go nuts.
best bet would be to check if there is any fluid, if there is check for smallllllll metal shavings. thats all i can think about.

Although it probably isn’t a rear wheel bearing, you could confirm by “slaloming” the car in a parking lot and seeing if the sound goes away when the car leans from one side to the other.

IE. A hard right turn that makes the noise go away would imply the driver’s side bearing would be bad (less load on it) and vice versa.

Other than that, my first stop would be the diff fluid indeed…good luck.