2006 Honda TRX680 Rincon Factory Service Manual, Page 504Get this manual
REAR DRIVING MECHANISM Coat new O-ring with molybdenum disulfide grease and install it into the groove in the output shaftApply molybdenum disulfide grease to the splines of the both sides in the universal joint and install it onto the output shaft until it is fully seated
Coat new O-ring with molybdenum disulfide grease and install it into the propeller shaft groovePut the final drive assembly on floor jack or other adjustable support and place the assembly under the main frameWhile adjusting the jack height, move the final drive assembly forward and connect the propeller shaft into the universal joint
Be careful not to disconnect the propeller shaft and universal joint