Abstract: A spline connection which comprises a spline boss having inward spline teeth; and a spline shaft engaged slidably with the spline boss and having outward spline teeth is disclosed. A header passage for a lubricant is formed along a core of the spline shaft and oil passages are further formed in the spline shaft in such a manner as to pierce therethrough radially from the header passage. At least one of the outward spline teeth of the spline shaft is provided at the top thereof with a groove crossing transversely the outer spline tooth so as to have the open end of the oil passage disposed in the groove.

Abstract: Herein disclosed is a shift fork lubricating system for use in a transmission of the type in which shift forks (4.sub.1, 4.sub.3) have their bearing portions (10.sub.1, 10.sub.3) slidably fitted and supported on a shift fork shaft (2) and their forked pawl portions (6.sub.1, 6.sub.3) formed at their leading ends for engagement with circumferential grooves (8.sub.1, 8.sub.2) of shift gears (7.sub.1, 7.sub.3) so that the shift gears (7.sub.1, 7.sub.3) are shifted by the sliding controls of the shift forks (4.sub.1, 4.sub.3). The bearing portions (10.sub.1, 10.sub.3) of the shift forks (4.sub.1, 4.sub.3) have their inner circumferences formed at their center areas with annular oil grooves (16.sub.1, 16.sub.3), respectively, which are axially elongated and always in communication with oil ports (14.sub.1, 14.sub.3) opened to the outer circumference of the shift fork shaft (2). The shift forks (4.sub.1, 4.sub. 3) have their inner circumferences formed at both the sides of the annular oil grooves (16.sub.1, 16.sub.