Not relevant to your '02 Viper, but for those with earlier model Vipers that came spec'd with Dexron III like mine 1996, switching to Syntorq/Mopar Synthetic was recommended to quiet neutral gear rattle. I changed to it years ago but decided recently to revert, believing that more frequent changes of a less expensive fluid was a better long term strategy. After putting in the Dodge recommended updated ATF+4 and driving for a 1,000 or so miles, I find smoother shifting and it seems quieter overall, plus I can do a fluid change for the price of just one quart of the Syntorq.