Chrysler Repair: Chrysler Concord 1996 transmission no shift, obd ii code reader, chrysler concord

Question
trans wont shift fluid & filter changed used atf+4 nothing unusual in pan dont know what fluid was in before dont know history of this car. code reader found no codes other then o2 sensor

Answer
Hi Mike,
Was that readout done with an OBD-II code reader plugged into the socket under the dash next to the steering column? If not, then you need to do that, for free at an Autozone parts store, or for about $40 at an independent garage. Get any 4-digit fault codes and let me know. If you used the ignition key approach that only reads out the OBD-I codes from the engine controller so that would explain why you got no trans codes. Otherwise about the only thing that will shut down shifting so completely is the trans relay which is #9 in front row of the power box under the hood. Specific trans faults will shut off that relay also and that is then called "limp-in mode" which is probably the name of your present situation.
Roland