I have a 2000 GMC Sierra, 200k miles, 5.3, 4wd. Yesterday after I had been driving for about 15 minutes around town, I was stopped at a stop light on a slight grade. When the light changed, I starting to give the truck gas but it did not immediately go like it should. It kinda felt like it was creeping up the hill very slowly for a couple seconds. Then after a couple seconds it started to go like normal. Do this sound like a transmission problem? What could it be?