One problem related to transmission not go into gear has been reported for the 2014 Jeep Wrangler. The most recently reported issues are listed below.
I was driving downhill on the freeway (just east of snowville, ut) at approx 70 mph (speed limit 80), when the Jeep suddenly shifted into a much lower gear (1st or 2nd). Of course we spun out--first one way, then the other as I fought for control I either got it into neutral or it went into neutral itself and I regained control and got it to the side of the road. I was very lucky not to have rolled the vehicle or hit other vehicles, and my wife said she would have rolled it. After I got it to the side of the road, it would not go into gear for sometime and the engine light went on. After three or four tries, it eventually went into gear and the engine light stayed on, and we drove the 60 miles or so back home at a much slower speed. I drove it to the dealer the following day and they said to bring it back on Monday, which I did and they kept it several days but could not find the problem. My wife won't drive the vehicle at all now, and I am afraid to drive it at freeway speeds, though it now seems to be driving ok. Of course I'm concerned that this might happen to me again, but I'm also concerned that it might happen to someone with less driving experience and kill someone.