I changed out my batteries because they didn’t meet the cold cranking amps. Mine was a electronic/ low voltage issue. The stock solenoids are junk buy some aftermarket ones. Replace the solenoid and the pressure governor sensors. Is it the original transmission? If so how many miles?

 

Stock ones are so bad there starting to warranty them out at the dealership. Try new upgraded ones from a reputable company. Don’t get them from Sun coast diesel. ATS OR REDLINE is what I would buy. Cheaper than a new transmission before you commit to it.