I have never tried speed shifting. One of my questions is on shifting the 6 speed transaxles on the fly. When I go out today, I will give it a try. This mower is relatively new to me, so I really do not know the history on the belt. With the engine not running and the brake engaged, the belt feels and looks loose. From what I have read, there are lots of negative posts on the Spicer, with the Peerless being favored. Any particular reason you are partial to the Spicer? WayneL