This issue has recently been happening with my Cadillac SRX. I have recently installed new pads and rotors on the front wheels and rotated the tires. When doing the brakes I noticed a stabilizer rod was broken but was not having any issues so I didn’t jump right on it. The vibration got worse so I just repaired that and it seemed to help but there is still a vibration at that speed when slowing down. I thought maybe the tranny was not down-shifting correctly but I dropped it into neutral and there was still the vibration when slowing.....and I am not touching the brakes when this happens. It needs to go to the shop to replace an exhaust manifold gasket, I will have them take a look. Will advise what they come up with.