2010 Polaris Sportsman 850 Service Manual, Page 234Get this manual
FINAL DRIVE Setting Ring Gear Backlash
NOTE: Ring gear backlash is set at the factoryNo adjustment is required, unless the front cover is replaced or the backlash screw has been tampered with1The backlash screw has locking agent that holds it into placeUse heat gun to lightly heat up the locking agent on the screw4Set the gearcase uprightRotate input shaft at least timesThis ensures the ring gear completes one full rotationIf tight spot is felt during rotation, loosen the backlash screw another 18 turn and perform step againRepeat this procedure until the pinion shaft rotates smoothly times (1 revolution of ring gear)