I have an 06 Vinson automatic and when under load, either accelating or decelerating it whines like a turbo charger. Doesn’t do it when just maintaining speed (just enough throttle to balance between faster and slower) and doesn’t happen in neutral

Happens in both 2 and 4 wheel drive. I think it’s the rear differential but I’m not sure if it’s normal or if my gears are going.
Anyone care to chime in if you have a noisy differential or am I just being overly critical?
Thanks