Do not interchange Transmission Control Modules with previous year transmission control modules. If a same year TCM is being used from a different vehicle, the following procedures must be performed:
The Transmission Control Module is located on the right fender inner panel, in the engine compartment. It is held in place by four mounting screws.
NOTE: If the Transmission Control Module has been replaced, the following procedures must be performed:
P1776-SOLENOID SWITCH LATCHED IN L-R POSITION
When Monitored and Set Condition:
CHECKING SYMPTOMS AND POSSIBLE CAUSES
LOW BATTERY VOLTAGE CAUSING SYMPTOM
TRANSMISSION PAN HAS EXCESS DEBRIS
DEBRIS IN PAN CAUSED VALVE BODY DAMAGE
INTERMITTENT CODE P1776
I would have the transmission serviced fluid and filter changed and see if that solves the problem..First check the battery condition. just because it starts dont mean that the battery is good it should be load tested. any auto parts store will do this for you free.