VEHICLE OFTEN DOES NOT ENGAGE IN GEAR. EVENTUALLY WHEN IT CATCHES GEAR, THE VEHICLE LUNGES CONSIDERABLY IN GEAR FORCING THE CAR TO JERK FORWARD. IT HAPPENS MORE OFTEN WHEN GOING SLOW IN TRAFFIC OR GOING UP AND DOWN HILLS. VERY UNSTABLE IN THESE SITUATIONS. IN ONE SPECIFIC SITUATION IN TRAFFIC, CAR DID NOT CATCH GEAR AND THEN WHEN IT ENGAGED, JERKED FORWARD INTO CAR IN FRONT OF ME.