What does P0780 Shift Malfunction mean, do I need a new transmission?

P0780 indicates a shift solenoid malfunction. If so, you probably wouldn't need a complete transmission overhaul, just some valve body work to replace the solenoid(s). P0780 doesn't specify which solenoid so some diagnosis would be required. Here's a directory list for you: http://repairpal.com/honda-repair-in-fairburn-georgia

wait before replace the trans. check your thermastad ,if need to replace get dealer part,flush trans oil ,get the tran oil for your car no jobber oil,place a tran filter special magnetic transmission filter 3/8 hole size,pick metal frament that goes on the return cooler line ,note good to add trans cooler a small one . note check replacing the trans made test on the computor PCM need reprogram or replace.check evap at gas tank check valves, stay open