I have a 1998 honda odyssey. It has an auto trans. The guy at auto zone pulled a code of P0740. Does anyone know what this means and how much it will cost to fix?

P0740 = Torque Converter Clutch Circuit Malfuction.
Something is up with your torque converter lockup solenoid and/or wiring. An easy senario would be a bad connection external to the trans. Worst case? an internal job that would require removal/replacement. I don't know anything about the 1998. No TC lock will cause the trans to run hotter than normal and will wreck your fuel economy.

Joel