Forward or direct clutch snap ring, if 2/3 is in the pan, you should pull trans and replace the snap ring before the rest comes out and damages something. A PITA, but fairly low cost as a DIY. If you are lucky it will be the forward most clutch, it’s easy to get to. Are you running a shift kit? I ran one in my 01 for awhile until about 2” of the same snap ring wound up in pan. I pulled out the kit and it’s running fine, but I plan to pull mine apart soon and freshen it up. Good luck!