The automobile industry was in a fateful crisis from Japan's defeat in war and the chaos that followed it. However, military procurement enabled a recovery and the combination of the accumulation of technology from before the war and present material resulted in the development of an automobile above expectations.
The chassis of the Toyota Jeep BJ was based on the SB-type 1-ton truck (with an S-type 995cc engine) that was originally released in 1947. For that reason, at 2,400mm the wheelbase about 200mm longer than that of the Jeep, and the body was also a size larger. The SB-type compact truck was commonly known as the Pony Toyota (and later the Toyopet Truck), and because it was designed as a small transport vehicle that could also double as a passenger car, its suspension settings were likewise soft. These characteristics were carried over into the Toyota BJ-type, so it gave a surprisingly comfortable ride.
The engine was a 3,386cc water-cooled in-line 6-cylinder B-type gasoline engine. Jeeps being built at that time had a side valve construction, but the B-type engine was an OHV (Over Head Valve) type. The engine was originally designed in 1937, with the first prototype completed the next year in 1938, after which it was installed in the GB-type truck, the KB-type truck, and the BM-type truck, being primarily an engine for 4-ton class trucks.
The capacity of the B-type engine when it was first developed was a maximum output of 75HP/3,200rpm, and a maximum torque of 21kgm/1,600rpm. Later these specs were improved by boosting the compression ratio and through other refinements, so that whereas the first model Toyota Jeep BJ model had a maximum output of 82HP/3,000rpm and a maximum torque of 21.6kgm/1,600rpm, by the late model version the power had been boosted to a maximum output of 85HP/3,200rpm and maximum torque of 22kgm/1,600rpm. This meant reserve power for the size of the body it was mounted in, so the Toyota Jeep BJ came without a LO range subgear.
The Toyota Jeep BJ was completed in 1951, and first unveiled that same year at a public showing of Toyota vehicles. There were 26 Toyota vehicles displayed at this event, and during the 3-day period the attendance amounted to some 200,000 people. Moreover, the design of the Crown was begun in 1952, with the first Crown model built in 1955.