THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT MAY HAVE SHUDDER OR CHUGGLE WHEN ACCELERATING AT LOW SPEEDS OF 12 TO 15 MILES PER HOUR OR 19-24 KILOMETER PER HOUR IN SECOND GEAR. ALSO SAME SHUDDER OR CHUGGLE WHEN ACCELERATING AT SPEEDS OF 30 TO 40 MPH OR 48-64 KILOMETER PER HOUR, WHEN ACCELERATING IN 6TH GEAR. TECHNICIAN WILL FIRST CHECK LATEST VERSION OF PIP5303 NEW SERVICE CALIBRATIONS FOR THE ENGINE CONTROL MODULE AND TRANSMISSION CONTROL MODULE. THE CALIBRATION UPDATE MAY NOT TOTALLY ADDRESS SHUDDER OR CHUGGLE CONCERNS. THESE CONCERNS ARE DUE TO NORMAL OPERATION OF THE AUTOMATIC TRANSMISSION AND THE TORQUE CONVERTER CLUTCH.