SOUNDS LIKE IT NEEDS TO COME APART AND THE MESH OF THE GEARS NEEDS TO BE CHECKED. IT REALLY SOUNDS LIKE SOMETHING IS NOT LINED UP. PAY ATTENTION TO THE RING AND PINION GEARS. IF YOU DON'T SEE ANYTHING CLEAN THE RING AND PINION OFF GOOD AND USE EITHER A PATTERN GREASE OR WHITE GREASE AND SEE WHAT THE CONTACT PATTERN IS. IT SHOULD BE NEARLY FULL CONTACT, IF NOT YOU WILL NEED TO ADJUST THE PINION EITHER UP OR DOWN. DO REMEMBER ONE THING, STRAIGHT CUT GEARS ARE INHERRIANTLY VERY LOUD. THAT DOES SEEM ALITTLE TOO LOUD.