Bought a 2019 4x4 Rebel in Aug. 2018...since that time I have experienced the most irritating humming noise at around 1500rpms or 55mph mostly when I remove my foot from the accelerator. This phenomenon appears to be more prevalent when there is something in the backs seat. The decibel level is so base like it hurts my ears to the point it's difficult to drive. Anyone know if there is a fix for this?