Got my replacement castle sidewinder 4and 5700 kv motor back from castle. Installed in my slash 2wd mostly stock as I can tell. Only things I've done to it are put the castle creations system in and added a pink wheelie bar since that's all that was in stock at the time. Couldn't tell you pinion size but think its 22t and 86t spur gear. Runs 2s 5200 zeee packs. It wont keep the front wheels down now.