The dealer was very confident the noise was the belt slipping. I was instructed to check belt tension from the bottom, not the top. There should be roughly 10mm deflection when pushed fairly hard. When checked from the bottom my belt deflection increased to 1.5-2". I have now tightened the belt to the dealer recommended 10mm deflection and the loud bang/gunshot sound has stopped. I'm now worried the I may have tightened too much. The bevel box was whisper quite before but now makes a very distinct sound during deceleration. It sounds like a generator winding down.
