The Field Marshall Series 3A production comenced with Field Marshall Serial Number 15207, Early Series 3A tractors did not have the pressurized cooling system this appeared on tractor 15662 and followed thereafter. An early Series 3A can be very easily mistaken for a series 3 and the only way to tell them apart is by the serial numbers. Many series 3A tractors have been repatriated from country's to which they were exported when new such as Australia, Argentina, Africa, & Canada in their original green livery.