Hi, just joined the forum, I have never seen a transmission, but I am new to this hobby. I did however find what is called a jack shaft kit... I found it on bike berry, it basically attached to the frame right below the motor, and brings the power to the bike chain side, then powers the main peddal sprocket so you can use your rear derailleur gears. The kit includes new peddal crank assembly that allows motor to spin the sprocket without turning the peddals. Haven't tried it yet but will eventually...