2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 305Get this manual
REAR DRIVING MECHANISM GEAR CASE ASSEMBLY NOTE:
When the gear set, bearing, andor gear case has been replaced, check the tooth contact pattern (page 16-1 O) and gear backlash (page 16-8)Keep dust and dirt out of the case and cover
Clean the mating surfaces of the gear case and cover, being careful not to damage themBlow compressed air through the breather hole in the cover
Apply grease to the lips of new ring gear oil sealsInstall the oil seal into the case cover with the flat surface facing out until it is flush with the coverTOOLS: Driver Attachment41 52 mm