Dodge Avenger Transmission downshift


My 2008 Dodge Avenger SXT with 49,000 miles started missing the downshift from 4th to 3rd gear. 4 Cylinder with 4 speed automatic. Symptom is as if it goes into neutral. First, the dealer reprogrammed the power control module and transmission control module per a service bulletin. Not fixed. Next they had the car five days and on advice from Chrysler, replaced the ignition. ( $370 bill ) Problem persists. This car has a lifetime power train warranty. Ideas and suggestions please.