What makes an 95 Cadilla Seville jump when placed in gear?
It can be fast idle or it can be damaged motor mounts.
1st connect the electricity, 4 straight wires, it's easy. Then Attach the long gear belt to the already spinning large gear. Add the small gear to the end of the belt. Attach the large gear on top of the small gear just placed. Attach the short gear belt between the new large gear and the small red existing gear. Good luck.