Chrysler Repair: 97 Sebring: limp-in mode, dipstick tube, torque converter

Question
I have a 1997 sebring, It starts good and runs fine , UNTIL I drive over 10 miles , at that time the check engine light comes  on the only thing that changes at that time  the rps go up slightly ,But when I have to slow down or come to a stop ,when taking back off it will not shift out of frist gear , I have to pull over, shut the car off , then restart , And I am good to for another 10 -15 miles.After doing this for at least 3 different times. The check engine light will go off. and will not come back on untill I drive again over 10 miles ,then it starts all over again. I have replaced the output sencer , with no luck . I am at my witts end.     HELP !!!!

Answer
Hi Randy,
It appears to me that the device called a torque converter lockup, part of the transmission, is unlocking itself (when the rpm's go up slightly) and then the transmission controller puts the transmission into 'limp-in mode' which is a self-protective status where the transmission will only run in 2nd and reverse. There is an underlying reason why this is happening and to find out why you need to get a fault code readout using a code reader that plugs into a socket under the dash. There will be a 4-digit code(s) that will be helpful to decide what needs to be done. Ayou can get a free code readout at nationwide parts stores such as Autozone or an independent repair shop will charge around $40. Let me know the code number(s) and we'll go from there.
When you write back tell me the size of the engine, and whether this is the convertible or the coupe model. You might want to check the level of fluid in the transmission via its dipstick which is in the side of the transmission If you need fluit add only ATF +4 type and don't overfill it. You add it via the dipstick tube.
Roland