Abstract: A reverse gear squeal-preventing device for a transmission having a main shaft, a counter shaft, and a reverse idler shaft arranged substantially parallel to each other within a transmission case. The main shaft is provided with forward stage main gears and a reverse main gear. The counter shaft is provided with forward stage counter gears and a reverse counter gear. The reverse idler shaft is provided with a reverse idler gear. A shifting and selecting shaft is controlled by a shift lever to provide axial movement at the time of selecting and pivotal movement at the time of shifting. The shifting and selecting shaft is provided with an interlocking plate for preventing malfunction. There is provided a forward stage-synchronizing mechanism which is actuated at the time of reverse shifting so as to prevent gear squeal.