During the 1930's Diamond T was selling more trucks than both White Motor Company and Mack. Diamond T was fifth behind the big three automakers and International. Many manufacturers experienced very difficult times during the Great Depression years but Diamond T actually had record sales of over 4,100 trucks during the 1933 model year. The company was very well known for their quality medium and heavy-duty trucks. It's been said that Diamond T actually outsold many rivals because their trucks looked better. In other words, Diamond T successfully integrated heavy truck design with style.

Two things many truck enthusiasts point to about the Diamond T truck design are the distinctive grille bars and the top opening by plated clamps. Design changes at Diamond T really began during the 1920's when trucks were not known for their styling. In fact, trucks were known for anything but smart styling until Diamond T started redesigning. Diamond T was really the leader in changing the appearance of medium and heavy-duty vehicles and probably the best example of their restyling came out in 1933.

Diamond T's reputation was as a builder of heavier trucks, typically one ton and larger. The company built what most considered quality heavy trucks with style. During the First World War Diamond T built more than 1,500 Liberty Trucks for the military. During World War Two, when the company produced over 50,000 vehicles, many of these vehicles were purchased by the British Purchasing Commission. This included half-tracks, army wreckers, tank tractors, and tank movers.

The 1937 Diamond T Pickup was built with a six cylinder Hercules QX Series engine. Hercules was established in 1915 in Canton Ohio. The Hercules engines soon became the standard for independent truck manufacturers. Hercules also built engines for the marine, oil and farming industries. During World War Two it's said that Hercules was sending about 18,000 engines per month off their assembly lines.

The 1937 Diamond T's had bow fronted grills along with new and broad fenders. The windshield was at a 30-degree angle. The dash panel with its large diameter “airplane type” instruments was largely from the 1935 model. Another feature with the 1937 Diamond T Pickup was an electric clock on the dash. You would not have found that on another truck brand in 1937. Also on the dash was a cigarette lighter.

In addition to this, in 1937 Diamond T would offer options to the truck buyer, one of which was oversize chrome hubcaps. This is another example how Diamond T used styling to help beat competitors.

The 1937 model came out with a three speed manual transmission.The truck had a weight of about 8,000 lbs with a spring suspension.

The Diamond T Model 80 Pickup had a wheelbase of 119.0 inches and up to a bit over 9 feet of loading space.