My 2016 Journey with 3.6 engine threw a P0740 code. My mechanic put a computer on the car and drove it. The computer said "torque converter not in range." The mechanic said it meant it was slipping a little. But the tachometer did not show the slippage. O'Reilly's auto Parts store said it was a torque converter solenoid. Would a transmission oil change help a solenoid?

 

Late response but…Wouldn’t hurt trying that first, fluid does wear out. I believe TC solenoid is accessible
with side cover removed with transmission in place. Even factory parts is less than $50. Try to avoid full rebuild.