1st and 2nd are selected by the same "slider". 3rd and 4th by the same slider (but diff from 1st and 2nd). 5th and reverse are in the rear of the "4sp box". Not sure if they share a slider. There is a bearing in the input shaft. That beraing can grind and whine like MF and change pitch with gear. When the input shaft and main shaft spin at the same speed (4th gear?) then all is quiet.