The Screw is the cheapest item from this partsfiche.
A sample from the products for the Transmission (model K1/k2/k3) include: Seal,oil(28x38x7.5), Shim(25x34x1), Retainer, Gear,second Drive (nt:17).
On this parts fiche the O Ring(d:1.9,id:19.8) is the most specified component.