Chrysler Repair: chrysler concord 93 transmission, chrysler concord, solenoid switch

Question
i have a 93 Chrysler concord 3.3liter. when you put it in gear   
and start driving it will run for a while, then it will lose the overdrive (usually this is when we hit a bump). we still have low,third, and reverse. you can let it sit for a while,restart then it will work again. this process keeps repeating its self. what do you think the problem is? i thought that the cylinoid and sensor may be bad. i don't know where they are located.  
                                thank you

Answer
Hi Alton,
The quickest way to find out what is wrong is to readout the transmission controller for any fault codes that may stored in its memory. This is accessed via a blue plug to the right of the steering column, under the dash. An obd-I code reader with the data link connector that matches that plug is necessary. The code reader has to be a Chrysler DRB II or equivalent type. An independent transmission shop may have such a reader as would a Chrysler dealer. If you can get the two digit fault code(s) FOR THE transmission* and tell me what they are we can compare to the shop manual to see what might be wrong. In the meantime I would recommend checking that the fluid level is correct by looking at the dipstick. Only use ATF+4 to add fluid if needed, but don't overfill it.
It could be a solenoid switch is dropping out. But the code read will tell us that, and which one it is, if so. The solenoids are in the big box on the front side of the transmission.
Roland
*the engine fault codes are also two digit, so the code reader has to be instructed to get the codes from the transmission, not from the engine controller. Otherwise a false code reading will be the result.