700R4, 4X4 Silverado 2500

Had this tranny rebuilt a while back, maybe 9or 10 months ago. The guy does a 12 month warranty. Got the tranny installed, filled and TV cable adjusted. Took her for a 20-30 minute drive and everything seemed fine. A day or 2 later took her to the dump and lost reverse. Forward gears catch but are noisy after about 5-10 mph. The guy asked about my transfer case, The fluid level and color and asked me to drop the pan and check for debris. Had to get it towed home. It seemed like the transfer was binding a little so i pulled it and ordered a rebuild kit. Checked the tranny fluid and it was pink and at the correct level. I got caught up in some other projects and just now got around to pulling the pan. I found copper or brass washer looking material about 3/4" inside diameter and some steel pieces as well. This tranny has less than a hundred miles on the "rebuild". Any ideas or opinions on my tranny situation would be appreciated. Thanks all.