This weekend I had a similar experience. I did a rapid deceleration due to traffic dropping from 65mph to 30mph. I got a clunk sound. Engine light came on, would not go out of 3rd gear. I got off next exit. Pulled into a 7/11 to get a soda and figure out what to do. Got back in the Jeep. Started up fine, engine lite still on, got back on the Interstate, and it shifted fine. Monday, the engine light was out, still shifting ok. I called the dealer who said to get back to them if it happens again????

BTW, 2006 Liberty Limited CRD, about 3 months old, 2800 miles.

----------update-------------
I went ahead and filed a complaint so there is a record of another failure.