G-630: The “other” WWII 2-1/2-ton truck

by David Doyle

Studebaker’s US6

Though not widely recognized in the States, the Studebaker US6 was a mass-produced vehicle. Shown here are just a few of the 197,678 vehicles built in South Bend, In. An additional 22,204 trucks were license-built by Reo Motors in Lansing, Mich.

Designed by Studebaker (which built the bulk of these trucks), the US6 was an alternative to the 2-1/2-ton GMC CCKW and the International M5-H6 6×6 trucks. Studebaker’s huge South Bend, Ind., works began turning out these vehicles in June 1941, and continued through August 1945, with 197,678 rolling out of what was once the nation’s largest wagon maker. These were joined by 22,204 identical trucks built by Reo Motors in Lansing, Mich., indistinguishable from the Studebakers, save for the data plates.

Initially, the both the long and short wheelbase US6 cargo trucks were equipped with all-steel beds. As the war wore on, however, steel shortages resulted in wooden and composite wood and steel beds being used as seen on this restored example belonging to David Firstman.

When equipped with a winch, the short wheelbase model was designated the US6U2 and the longer wheelbase, the US6U4. The “Studebaker” nameplate on the grille was dropped in 1942 per a government order.

Like the CCKW, the US6 was built in both long (162”) and short (148”) wheelbase versions. Studebaker’s company photographer caught this short wheelbase US6 without winch, Studebaker model number US6U1 truck undergoing testing at the company’s own South Bend proving ground.

Regardless of maker, the US6 was powered by the Hercules JXD six-cylinder engine. This engine also powered the White M3A1 Scout Car and the Ford M8 and M20 armored cars.

Because so much of the US6 production was sent to Russia, (which has notoriously harsh winters), the vast majority of these trucks were built with closed cabs. The irony of this is that the World War II Standard (open) Military cab — used on almost every other truck — was developed by Studebaker! However, the weather prevented its use on all but about 10,000 of the Studebakers between December 1942 and March 1943.

These trucks were produced in short (148”) and long (162”) wheelbases. The US6 used the same transmission and transfer case as the GMC CCKW. Even the Timken axles were the same as those used on many of the GMCs.

The brake system employed by Studebaker was not the Hydrovac system that GMC used. Instead, Studebakers were equipped with a vacuum-boosted brake system.

Large numbers of Studebaker US6 trucks were supplied to the Soviet Union via the Persian Corridor in Iran under the USA’s Lend-Lease program. The truck became affectionately known to Soviet troops as the “Studer.” Joseph Stalin even sent a letter of appreciation to Studebaker, in which he thanked them for the superb quality of the US6.

In addition to the common 6×6 version, the US6 was also produced in 6×4 form. Since the 6×4 version was intended for on-road use only, its weight classification was five tons, whereas the 6×6 version was rated using the traditional off-road system of 2-1/2 tons.

Today, the US6 is not wildly known in the United States  nor as easily recognized as its 2-1/2-ton GMC counterpart, the CCKW. The s largely due to these trucks’ export, en masse, to the Soviet Union. In fact, these trucks’ power and reliability became  so popular with their new Russian owners, that “Studebaker” came to be accepted as  a slang term in the Russian language. While in this country, we might say something or someone was “built like a Mack Truck,” saying the same using “Studebaker” in place of “Mack Truck” would weigh in with the same effect in the Soviet Union.

Some of the US6 trucks were built with open cabs as seen here. This cab looks much like the open cab of a CCKW, perhaps leading some to believe that the Studebaker was a copy of the GMC. In fact, the open cab was developed by Studebaker, and then installed on the GMC and most other 6x6s. National Archives and Records Administration photo.

The US6x4 was built in three configurations; the U6, the short wheelbase tractor like the one owned by Guy Jenson (pictured), the U7 long wheelbase cargo without winch, and the U8 long wheelbase cargo with winch.

And while popular folklore mistakenly implies the US6  was a copy of the GMC design, imitation is the highest form of flattery. The Soviet Union was unashamed to “reverse engineer” the US6 and build unlicensed copies, known as the ZIS-151.

The US6 was also built as a dump truck. When not equipped with a winch, as shown here, the model designation assigned to the rear dump was U10.

While many US6 were delivered to America’s allies as part of Lend-Lease supplies during WWII, many trucks were also used during the development of the Alaskan Highway. This US6 “survivor” was photographed in 2008 in Wasilla, Alaska. Alfred DeVaux, Jr.

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