trouble code of p0740

I had my smog checked and the report came back with this code. It says it is a torque converter clutch circuit malfunction. I need to know what this is and how much it is to fix. Any info will would be great. Thank you ...

Here's an interesting link...

http://www.rv-coach.com/current_category.181/Forum.39568/forum_thread_full.html

Which tranny do you have 3 or 4 speed? What year?
Ron

I have the same problem for my 2000 T&C. It is 4 speed auto. Even with the engine check light on with two codes (P0700, P0740), I don't have any other driving problem. Tans fluid level is OK with great bright pink color. Gas mileage seems slightly less.
Do I have to do any action? Will it cause any further damage to the car if I don't do anything?
Thank you


Mike