Aluminum through bolt case (3.250" bore), 35-spline lightweight steel spool, MW 35-spline 1350 series pinion yoke, ball / tapered bearing pinion support, large pinion 9310 pro gear. All MW thirdmembers include shipping / storage transporter and 3 quarts of gear lube (58 lbs) Installation - Service instructions can be found on Service Bulletin #0038