One problem related to transmission slip out of gear has been reported for the 2003 Chevrolet Impala. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Chevrolet Impala based on all problems reported for the 2003 Impala.
The transmission began failing within 3 weeks of purchase. Transmission would slam and jerk in gears and finally began not shifting out of 1st gear until 50 mph. Was fixed and then one week later began failing again. This time car would not shift into 4th gear but instead just slip gear and rev engine. Transmission finally locked into 3rd gear and would not drive in any other gear. This all occurs within the first 2400 miles and 1 1/2 month of ownership.