Once the dealer did the 1st service , It seemed the engine was noisey to me. So i switched to AMS 10/40 and everything was smooth and the transmission was smooth , Then the next oil change i put in mobile one (onsale for 7.99 qt) and walmart oil filter, everything seemed ok but the transmission was clunky with every gear change. So saturday i chose AMS 20/50 and K&N oil filter . The clunking is gone and WOW really smooth (engine too). Took it for a long ride and im impressed. So you get what you pay for..