The 2004 reverse setup requires a left handle control switch with the reverse button, a compatible wiring harness leading to that switch, the special 22 degree flywheel, and a team secondary clutch that works backward. Optional is the oil pump that works backward. So you can buy all of these parts for an 04 RMK, off of EBAY and install them on your 03. If you don't have a 151, then the track tends to dig a ditch when put in reverse.