I have a 2015 RAM 1500 4WD with a Hemi and 8-spd trans. It has 115k miles on it-all highway/some towing. Sometimes, at highway speeds (75-80 MPH), the truck will suddenly and aggressively slow down for about a second, like I'm braking really hard, but I'm not. It is almost always after going over some decent sized bumps, like a 20 foot section of roughly patched pavement, or maybe an uneven bridge connection...something that makes my truck bounce pretty good for a second or so. Usually, it is after I let off the gas due to the bounce. So I go over uneven pavement, let off the gas then a second of heavy deceleration. I do not notice any noise or vibration before, during or after the deceleration. The deceleration feels like I'm cruising in 8th gear and suddenly downshift into 3rd or 4th, but I do not notice the transmission downshifting or the engine reving. I could also describe it as momentarily applying a wind-brake. Anyone have any clue what this could be?