Velvet Drive Noise - Not Damper

[Tethys26]

I pulled the red gear off my 71C w/2.57-1 to replace a leaking rear seal. I figured while I was at it, I´d replace the adaptor plate gasket and red gear gasket as well. To do so, I pulled the ring gear/input gear from the plate, but left them attached with the snap ring as one piece. Everything went back together fine, but upon start-up, I noticed a healthy rattling coming from the red gear when placed into Forward. It does not make the sound in reverse or neutral. From what I can tell, it goes away by about 800-900 rpms. I don´t think it is the damper plate as I can hear a very faint, seperate rattle coming from the flywheel area.
So, I pulled everything back apart and found that the ring gear has small amount of play on the input shaft. I don´t remember whether this was there or not when I first disassembled it. Does anyone know how it is supposed to fit? I ordered a new snap ring to see if that will take up some of the slack, but I wanted to see if anyone here had any other ideas/advice. Thanks!
-Lloyd