torque converter problem? any ideas

[hihocadillac]

96 Deville. I was going up a steep mountain when my check transmission light came on. When I got to the Dealers garage he could not find a problem as light had gone off.
I am now driving on flat land. Check transmission light or sometimes traction control engaged light comes on, goes off after stopping car and no usage for 24 hours. I am being told 3k to cut into that area and determine if torque converter is the problem, my other option is keep driving until what ever it is goes out. any ideas? appreciate your help!
Thank you.