[CONRAD II]

Ok... Yesterday after leaving work I noticed that not long after starting my sut the check engine light came on. (I have only 17,000 mi) Luckily I have a GM dealer very close to my work and they were more than happy to run a diagnostic test on my truck. I thought the problem could by a symptom of not having my gas cap on properly or something simple like that. However, on my way to the GM dealer I stopped at a red light and turned the truck off. When I re-started the light was still on and my truck had little or no low end power, like it was starting in third gear or something. I drove that way until the next red light (about .25 miles) and then turned the truck off again. When I re-started the light was still on but the truck seemed to be back to normal. It started out in first gear and cycled through normally. When I actually got to the dealer and ran the diagnostic test everything checked out except the following code: P0740. The dealer said it had something to do with the torque converter, but he said that he wouldn't be overly concerned. He then reset things with the diagnostic machine and said to go ahead and drive it for a while to see if the light comes back on. He said he would be supprised if the problem presented itself again, because it was more than likely a glitch. About fifty miles later still no sign of a problem? I plan on visiting my Hummer dealer asap, but I thought you guys might have some insight. Any help would be greatly appreciated...