Vibration/Knocking noise from the rear at 20 to 30 mph?

Perhaps check to see if the lug nuts are tight. Always check the easy stuff first.

I have a 2012 Cadillac SRX as well and I think I am experiencing the same thing. It has been going on for about 3 weeks now. A "clank" sound that sounds like it's coming from the undercarriage area when I reverse or initially accelerate. It has 55,600 miles on it and has also had on time regular oil changes. Any thoughts?

I have a 2010 srx and I also experienced the clunk noise and vibration it was coming from the drive shaft . Had the drive shaft replaced and problem solved 52k on my vehicles Good luck : Anna

I have a 2015 SRX4 doing the same thing (rear end violently shaking) when accelerating from a stop. Its intermittent and seems to occur more when I've been driving it awhile. No warning lights. Taking it to the dealer tomorrow.

change the differential clutch pump fluid. part #GM 88863340. easy to do fluid NOT CHEAP!!! look on rear end there is a small [ump motor on bottom pull out and remove let fluid drain use brake cleaner to clean screen on pump and clean out resivoir. replace and fill while car is in drive on a lift if no lift then fill and drive a few miles then fill again. Good Luck