I recently purchased a 2017 RDX advance AWD in August with 80,000 miles on it. The vehicle has been extremely well maintained its whole life by an older gentlemen at the dealer, who continuously did preventative maintenance on it. However, I am experiencing a very strong downshift and slow down (jerk) at exactly 30 mph and 20 mph as I slow down to a stop every single time I drive the car. The car slows down significantly and feels as if it is slamming into gear. My head and other passengers shift forward every time this happens. People who ride with me ask if I am hitting the brakes, that's how significant it is.

Below 20 mph the transmission makes a groaning and humming noise most times I am slowing down, that sounds like a dying whale, and is quite pronounced. When the car slows down, there is a sudden jerk and a noticeable drop in speed. I've concluded that it occurs most when the transmission downshifts from gear 5 to 4 (around 30-35 mph) and 4 to 3 (at 20 mph). It almost appears that when the car is in "drive" it shifts too early causing the car to jerk and slow down as if I quickly pressed the brakes (I.e. engine braking). This is a significant safety issue as the sudden jerk & slow-downs are unexpected for drivers behind me, especially since there are no visual indicators/warnings (e.g. brake lights don't come when this happens). Plus not to mention a waste of my gas, as I have to press the gas to get it back up the cruising speed needed.