MW aluminum through bolt case (3.812" bore), lightweight steel spool (40 spline), 1/2" ring gear bolts, MW 35-spline female pinion coupler, 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