The lowest price component in this Transmission parts-list fiche is the Snap Ring,25.9x1.2t.
Some items from this specific schematic: Gear-transmission Spu, Washer,28.1x34x1.0, Snap Ring,25.9x1.2t, Shaft,input.
With two applications this Washer,28.1x34x1.0 is the most specified part.