Phil's picture from the Master Parts Book with the exploded parts view shows two (2) sets of needle bearings in the "Clutch Shaft Gear" where the "Main Shaft" meets it (See Item 7). The main shaft is stepped, with 2 bearing surfaces for the different needle bearings to do their support job. The farther forward (smaller shaft step) of the two surfaces should be for the
smaller larger diameter (14 count) bearings and the larger diameter step for the
largersmaller diameter bearings (24 count) according to the below paragraphs in the GMC SM318 Rebuild Manual.
Edited to correct previous info.
