Gear Noise Help
so ive had 3.55s for a few weeks, and had them taken apart yesterday and looked at due to noise 30mph + . not really any over 70ish but up to there its noticeable with windows up and music off. The shop said everything looks good, they have done literally thousands of ford 8.8's as they are one of the oldest shops in the country. They used the corrects parts for the 2011, bearings and all. After browsing the internet, I am assuming it is simply the motive gears being noisy, as many pros themselves have had this issue with them.
my question..is there any additive that anyone here would recommend? I've heard good things, and also some do nothing. Thanks for any advice.