A shift-by-wire transmission system comprising: a gearbox configured and arranged to receive a rotational input and provide a select rotational output, the gearbox including a plurality of gear assemblies (150, 160 and180) operationally coupled together to provide the select rotational output from the rotational input; a shift assembly operationally coupled to the plurality of gear assemblies (150, 160 and 180) of the gearbox to selectively change gearing of the gearbox; the shift assembly including a shift drum having at least one groove guide (304, 36 and 308) having a select profile; an electric motor operationally coupled to the shift assembly to activate the shift assembly to selectively change the gearing of the gearbox; characterised by a manual shift override member coupled between the shift assembly and the electric motor, the manual shift override member configured and arranged to manually disconnect the electric motor from the shift assembly and activate the shift assembly; the shift assembly including a shift cam operationally coupled to the shift drum, the shift cam configured and arranged to complete a shift without the aid of the electric motor; the manual shift override member further having a first end and a second end, the first end including a manipulation head portion and the second end including external splines that engage internal splines of the shift drum; a decoupleable shift gear received on the manual shift override member between the first end and the second end of the manual shift override member; and a gear train operationally coupling the electrical motor to the decoupleable shift gear. a gearbox configured and arranged to receive a rotational input and provide a select rotational output, the gearbox including a plurality of gear assemblies (150, 160 and180) operationally coupled together to provide the select rotational output from the rotational input; a shift assembly operationally coupled to the plurality of gear assemblies (150, 160 and 180) of the gearbox to selectively change gearing of the gearbox; the shift assembly including a shift drum having at least one groove guide (304, 36 and 308) having a select profile; an electric motor operationally coupled to the shift assembly to activate the shift assembly to selectively change the gearing of the gearbox; characterised by a manual shift override member coupled between the shift assembly and the electric motor, the manual shift override member configured and arranged to manually disconnect the electric motor from the shift assembly and activate the shift assembly; the shift assembly including a shift cam operationally coupled to the shift drum, the shift cam configured and arranged to complete a shift without the aid of the electric motor; the manual shift override member further having a first end and a second end, the first end including a manipulation head portion and the second end including external splines that engage internal splines of the shift drum; a decoupleable shift gear received on the manual shift override member between the first end and the second end of the manual shift override member; and a gear train operationally coupling the electrical motor to the decoupleable shift gear.