2011 Arctic Cat 400 TRV ATV Service Manual, Page 104Get this manual
2Install the ring gear with shim in the gear case; then while holding the pinion stationary, rock the ring gear forward and back to determine if any backlash existsIf no backlash exists, install thicker shim and recheck
4Install the existing shim or 0.063 inshim on the cover side of the ring gear; then place the assembled gear case cover onto the gear case and secure with three cap screwsTighten evenly using crisscross pattern