His real name is Elwood G. Indiana, and his rank is that of corporal E-4. Crankcase was born in Lawrence, Kansas.
Crankcase's primary military specialty is motor vehicle driver, and his secondary military specialty is armor. He was building street machines by the age of thirteen and racing them at sixteen. He worked the stock car circuit for years, until a recruiting sergeant signed him up with promises of speed and glory. Crankcase graduated from Ranger School and Desert Warfare School, and attended the Special Air Service Tactical Driving School under the NATO Exchange program. He is a qualified expert in the M-16, M-1911A1, M-60, and TOW.
Source: Wikipedia, "[en.wikipedia.org/wiki/Crankcase_%28G.I._Joe%29 Crankcase (G.I. Joe)]", available under the CC-BY-SA License.