So this issue started a few days ago and I'm just looking where to start. I changed fluids in it and still when I start out on the bottom of a hill or dead stop when its warm its liek the engine just revs up until it feels liek shifting it only happens from 1st to 2nd. I did find some decent size pieces of metal that look liek they would be for a clutch or something along this lines. All started after I hit a deer and 3 quarts of tranny fluid came out all over the front of the truck. Any help would be great cuz I need a truck to get to work

 

your c6 might be low on fluid causing slipping. or, you might have lost all your friction material from filthy fluid and now have nothing to help work out trans pull. I'm debating this myself, on my auto. I had a Galaxie that pulled fine (C6 also) until I changed the fluid. I bet it had 1/3 of an inch of black thick clutch fluid in bottom of pan. After that, second gear was more notional than anything with clean fluid. Long 5 second pauses between 1st and 2nd that were greatly concerning. Didn't do that before I changed fluid. You might also have a vacuum modulator valve on outside of C6 that needs changing, theyre pretty cheap to try, about $20 or so, and very easy to change.