98 grand caravan won't shift and has service engine soon light on
 

Was driving my van and it shifted really hard and the service engine soon light came on immediately and stays on. My poor van has 198,000 plus miles. Had a rebuilt tranny put in several years ago and haven't had any problems at all with shifting until yesterday. Don't even know where to start! HELP!!!

If I knew nothing and had no tools, equipment, knowledge or skills on this problem. I would start with taking it to the place that rebuilt it several years ago.

the 1st diagnostic thing is to have a real scanner done on the vehicle to look at transmission codes, transmission data, and something called CVI values. that's where one needs to start in proper diagnosis. otherwise any attempt to internet fix it going to be just guess and speculate.

There are some transmission failures that are easy to guess at the cause because of frequency of occurances. your's is not one of those senarios

First thing I would recommend is to have the van checked for any stored codes in the PCM and the TCM and post the codes. This way we all can help you.

Had diagnostic done at auto part store. Says P0755 shift solenoid B.

Symptom:
P0755-2-4 SOLENOID CIRCUIT
When Monitored and Set Condition:
P0755-2-4 SOLENOID CIRCUIT
When Monitored: Ignition key is turned from the OFF to RUN position and/or key is
turned from the CRANK to the RUN position, then every 10 secs thereafter, or when a
speed ratio or pressure switch error occurs. All 4 solenoids are tested for continuity
continuously.
Set Condition: If a solenoid is On, power is momentarily interrupted, then reenergized. If
solenoid is Off, power is momentarily energized, then deenergized. If an inductive spike is
not sensed by the TCM, it is retested. If the solenoid fails 4 times the code sets.
POSSIBLE CAUSES
CHECKING SYMPTOMS AND POSSIBLE CAUSES
LOW BATTERY VOLTAGE CAUSING SYMPTOM
TCM CONNECTOR PIN 57 TO GROUND OPEN
TCM PIN 53 TO GROUND OPEN
TCR OUTPUT (SWITCHED B+) CIRCUIT OPEN
2-4 SOLENOID CONTROL CIRCUIT SHORT TO GROUND
SOLENOID CONTROL CIRCUIT TO SOLENOID CONNECTOR OPEN
2-4 SOLENOID SHORTED IN SOLENOID PACK
TCM OPEN GROUND
TRANS SOL PACK OPEN (2-4 SOL)
INTERMITTENT CODE P0755

The most likely cause is the solenoid pack. If you replace the solenoid pack you have a 50/50 chance that was the problem.

Husband is going to replace the shift solenoid this afternoon. Hoping it fixes the problem. Any advice when replacing it?

New shift solenoid is in and van is running great. Shifts really smooth:)