Gear shift fork insert

Abstract

An automobile transmission shift fork has its free branch ends formed with diametrically opposed notches with each notch engaging an improved plastic insert adapted to be received in an annular groove of a shift element. The insert has individual side walls interconnected by an intermediate spacer block designed for fixed conforming reception in an associated branch end notch. This arrangement substantially increases the effective insert side wall thrust face area relative to the groove abutting radial side thrust surface obviating the need to increase the depth of an existing shift element groove. The insert has an indented stop wall which engages its associated notch back wall upon fixed reception in its notch. The spacer block exceeds the notch depth by a predetermined differential dimension establishing paired insert raised edges adapted to ride on the annular groove base surface eliminating metal-to-metal contact therebetween. Each insert side wall thrust face is formed with mirror image convex curved surface portions at its ends providing rolling line contact with its groove thrust side surface during shift element tilting thereby increasing insert service life. The convex curved surface portions define, with their opposed shift element groove radial side thrust surface, lubricating oil reservoirs thereby improving oil distribution to the thrust surface.