possible transmission problem

I have a 97 GMC ext cab sierra K1500. Just recently, I started to get a noise, I believe in the transmission area, that is more of a clicking noise, not a clunk or grind. I even get it when I am in park and give it the gas. It only seems to happen when I give it gas. This happened once before, and somebody told me that it was a clip associated with the shifter on the column. I just had to put it in reverse a couple of times, then drive and it seemed to go away. It now seems to be more consistent. Just for info, I just replaced the starter, but I doubt that has anything to do with it. While I am driving, It gets worse the more gas I give, but if I glide a little, the noise almost goes away.

not too long ago on my 88 gmc sierra i had to replace the flywheel. the teeth were ok but the center had a large crack. my symtems were, trans. was slipping , grinding, clanking noise. but before all that check the flywheel guard first and make sure its not cockeyed or missing some of the holding screws.