Bought a 14 cruze diesel brand new drive a lot it has 161000, miles on it and after driving for 25 min or more come to a stop then let off brake and get a horrible clunk any feedback appreciated!!

I have a 2013 LT with A/T. 2k miles on it. Here is my problem I first noticed about 4-500 miles ago: after driving for about 5 minutes (35 mpg, 5-6 stop signs/lights) and parking the car for 5 to 10 minutes, when I start the engine and drive, the transmission will shift hard into 3rd gear...