Hi Toby,
The easiest way to check if it is your motor, is to open the drill up, and unsolder the 2 wires (or unclip the spade connectors - depending on the model) from the switch, then put these wires directly onto the battery terminals, if the motor runs at normal speed, then it's your switch that's at fault, if it still runs slow, then it's your motor. When ordering new parts, please note the Bosch 10 digit code (usually starting with 0601), as this will identify the type code exactly, and the variation, as there are a few machines with the same no's, GSB 18-ve2 etc, so the 10 digit code is important to get the correct spares, I hope this helps.
BTW the motors are sealed units, and apart from the brushes (if it has a seperate black brush cap & removeable brushes) the motors cannot be repaired, simply replaced, as they are sealed units.
Dave the tool repairer., June 2007
