"Grease monkey" is a general slang term for a mechanic or engineer and subsequently they are responsible for repairing trucks, equipment and power armor suits. They are usually found in the simulation's US-Einsatzhauptquartier in or around the tent opposite to the command tent.
Grease-monkeys keep the wheels of the U.S. military war machine oiled and rolling. Most of a grease-monkey's time (when not saluting superiors) is spent checking and dialing in schematics information for the Wintertaugliche T-51b-Powerrüstung units that have recently arrived at field headquarters.
Fallout 3 Add-On 
Operation: Anchorage vor.
