This ejector drum shaft transmits rotation from the threshing mechanism to the straw-ejector rotor. It spans the width of the separator housing and supports the drum assembly that throws straw clear of the rear of the combine. A bent or worn shaft causes the drum to run out of true, leading to vibration and uneven straw discharge. The shaft is machined to the original geometry so it aligns with the bearing bores and sprocket keyways without shimming. On replacement, inspect the bearings and seals in the housing and replace them if worn.