Hi guys! I have a 2002 F350 7.3 4x4 single rear wheel truck that I use as a commercial vehicle, when loaded I gross about 22,000lbs. It has 232,000 miles on it and has been quite trouble free, I think besides maint all I have done in an injector harness. Now I have contracted an annoying howl noise coming from under the truck, seems to be towards the backend of the truck. Starts in at about 30mph and quiets back down over 55mph but is likely still there just cant hear it anymore. At 32mph it is VERY loud. Definately mechanical noise and seems to be high speed. I am very maintenace oriented and have my trans flushed and filled every 30k, have drained and refilled the transfer case 3-4 times. I dropped my rearend (10.5) cover off to look around at the ring gear and pinion and all looked good with no abnormal wear. I refilled with royal purple synthetic with posi additive and made no diff in the noise. So I dont know what to think. I will say that when I am at 32mph and the noise is at its worst, if I let off the gas, the noise completely goes away. Truck has original joints and carrier bearing but cannot feel any slop in them. Would a bad carrier bearing make this noise under accel but go away when you let off the gas? Any thoughts? Thanks in advance!