Started car prior to leaving house. When entering car, placed car into run mode. Released parking brake and placed into drive. Service 4WD light came on with. When pulling out of driveway, I made a left turn which the car made a clunk noise in the front end. When driving a little further I topped the hill only doing about 15 mph. Once accelerating down the hill the car shifted and made a loud grinding noise. This prevented the car from traveling any faster. This also resulted in a needed emergency pull over on back road with no shoulder. Car was then parked, turned off for about 2 minutes in traffic. At that point car was restarted with no Service light. I began to accelerate and noise went away. Further driving brought light back on and off but no noise at this time. I have a concern this could happen at highway speeds resulting in a unessarcery car accident. There seems to be a high fail rate with these cars and the PTU. I would highly recommend extending the safety recall to all Jeeps with this brand PTU.