That wasn't a good idea. Now, those little plastic chunks are going to be all inside your tranny. If it were metal, itd be one thing because it'd just stick to the trash magnet, bit now you're going to have plastic pieces in your syncro rings and gear teeth. probably won't do any major damage, but'll probably make it hard to shift every so often when something gets stuck near a shift fork or syncro ring, if any gets stuck anywhere.

Part number M04797316, MTX speedo gear.