Hi, welcome to Just Answers,
Typically this code (P0740 - Torque Convertor Clutch failure) is followed by a faulty TCC solinoid on the transmission or by faulty hydrolic components in the transmission. I would replace the solinoid first, clear the codes and see if the problem persists...since your not experiencing any other symptoms, there's a good chance the transmission isn't due for an overhaul. Also, if you haven't already you should flush thetransmission fluid with Honda ATF...to help ensure the internal transmission components stay good.
Location of TCC solinoid.
Nothin special, just bolts on and off...there is a little o-ring on it, just make sure you have a new one on and I like to spray them down with WD-40 to help ease the install. The TCC is the same as the Lock Up solinoid..don't worry about torque value it is in inch punds (little torque) and most people don't have access to an inch pund torque wrench...tighten the bolt snug with a 1/4 inch rachet.