QuestionMy 99 Concorde 175K, (automatic tranny)when de-accelerating @ 38mph, it suddenly & violently downshifts to low gear by itself. It stays stuck in low gear until the car ignition is tunred off/on. Then, it's ok again.
AnswerHi Robert,
I believe that it is dropping into 2nd gear, not low gear. What is likely happening is that the transmission control module has sensed something to be wrong with the way the trans is responding to its directions. Depending upon the fault it may put the trans into 2nd gear as a strategy to reduce the chances of damage. This is called "limp-in mode".
It will temporarily be lifted when you stop the engine, but revert again quickly to driving only in 2nd gear, either when shifting up from low,or when decelerating.
The best thing to do is get a diagnostic readout of the memory of the controller via a 16-pin plug that is located under the dash using an OBD-II reader that is capable of reading the Chrysler transmission memory. That could be done for free at an Autozone parts store, for maybe $40 at a good inderpendent trans shop (not a chain operation), or for $80 at a dealer. Ask for the four-digit fault code numbers, their names/descriptions, what the possible repairs are, and how much they would cost, and whether it is covered under any warranty. Then write back with the results and we'll compare that to the shop manual I have for the trans.
The repair could be expensive, so do take your time to get a proper diagnosis and maybe go to two shops for estimates and comparison of their warranty. I would not start with a chain-type trans shop because they are tooled up to do a replacement job not a repair job so that a more expensive repair may be the result.
Roland
