damn it, the tranny, iirc the 04 monte would of have the gen 3 blower and older style tranny, like a 03 gtp. you will likely need to do a pnp swap on it.

heres bills how to on that. Wiring a external PNP switch to an internal PNP transmission - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat