Shift control system for a multiple ratio automatic transmission with manual ratio ranges

摘要

A multiple ratio transmission for an automotive vehicle comprising a main gear unit with at least three ratios and an overdrive gear unit with a direct drive ratio and an overdrive ratio, and a control valve system that will permit upshifting and downshifting of the overdrive gear unit while inhibiting ratio changes in said main gear unit from either a second ratio manual drive mode or from a third ratio manual drive mode.