prob sometime in 1942

My hot money is 1943 before D-day.

Incidentally, while snuffling round Google for am answer, I unearthed the sphincter-twitching fact thet "Jeep" was coined for G-P; General and the P is US ordnance code for 80" wheelbase.

Found the following in Wikipedia you might findThe origin of the term "jeep"

There are many stories about where the word "jeep" came from, how it was coined, These, although they make for interesting and memorable stories, are not quite accurate.

Probably the most popular notion has it that the vehicle bore the designation "GP" (for "General Purpose"), which was phonetically slurred into the word jeep. R. Lee Ermey, on his television series Mail Call, disputes this, saying that the vehicle was designed for specific duties, was never referred to as "General Purpose," and that the name may have been derived from Ford's nomenclature referring to the vehicle as GP (G for government-use, and P to designate its 80-inch-wheelbase). "General purpose" does appear in connection with the vehicle in the WW2 TM 9-803 manual, which describes the vehicle as "... a general purpose, personnel, or cargo carrier especially adaptable for reconnaissance or command, and designated as ¼-ton 4x4 Truck", and the vehicle is designated a "GP" in TM 9-2800, Standard Military Motor Vehicles, 1 September 1943, but whether the average jeep-driving GI would have been familiar with either of these manuals is open to debate.

This version of the story may be complicated by the name of another series of vehicles with the GP designation. The Electro-Motive Division of General Motors, a maker of railroad locomotives, introduced its "General Purpose" line in 1949, using the GP tag. These locomotives are commonly referred to as Geeps, pronounced the same way as "Jeep".

Many, including Ermey, claim that the likelier origin refers to the character Eugene the Jeep in the Thimble Theater (Popeye) comic strip. Eugene the Jeep was dog-like and could walk through walls and ceilings, climb trees, fly, and just about go anywhere it wanted; it is thought that soldiers at the time were so impressed with the new vehicle's versatility that they informally named it after the character. The character "Eugene the Jeep" was created in 1936.

The term "jeep" was first commonly used during World War I (1914-1918) by soldiers as a slang word for new recruits and for new unproven vehicles. This is according to a history of the vehicle for an issue of the U.S. Army magazine, Quartermaster Review, which was written by Maj. E. P. Hogan. He went on to say that the slang word "jeep" had these definitions as late as the start of World War II.

"Jeep" had been used as the name of a small tractor made by Modine.

The term "jeep" would eventually be used as slang to refer to an airplane, a tractor used for hauling heavy equipment, and an autogyro. When the first models of the jeep came to Camp Holabird for tests, the vehicle did not have a name yet. Therefore the soldiers on the test project called it a jeep. Civilian engineers and test drivers who were at the camp during this time were not aware of the military slang term. They most likely were familiar with the character Eugene the Jeep and thought that Eugene was the origin of the name. The vehicle had many other nicknames at this time such as Peep and Pygmy and Blitz-Buggy, although because of the Eugene association, Jeep stuck in people's minds better than any other term.

it of interist too.