check fluid level? what gear oil you using? I had noisy duals, but I had 2 first gen cases which I was told had straight cut gears which in the later years were helical cuts. I put marlins 4.7 gears in the rear case and it quited it down very substantially. If you take everything apart take good pics and don't worry when the inside of your case looks like a spiderweb of fractures that's just how the castings look
