Diamond Reo Trucks For Sale

Diamond Reo trucks are known for heavy-duty frames, straightforward mechanical drivetrains, and vocational durability. Most units on the market are pre-emission conventionals and cabovers from the late 1960s through the 1980s, commonly powered by mechanical Cummins NTC, Caterpillar 3406, or Detroit Diesel 6-71 and 8V series engines paired with Fuller Roadranger 9, 10, 13, 15 or 18 speed manuals. Expect Meritor or Rockwell tandems rated 38k to 46k, steer axles in the 12k to 18k range, and wheelbases that reflect the original application. These trucks were built to work and are still sought for restoration projects, farm duty, logging, dumps, and low-mile vocational use.

Spec profiles vary by application. Highway day cabs were usually geared with 3.55 to 4.10 ratios for 65 to 70 mph cruise, while dump, mixer, and logger builds often carry 4.33 to 5.63 rears and deep reduction boxes like a 9LL for startability. Frames are often double-rail with heavy inserts, crossmember counts are high, and many units ride on Hendrickson RT or RTE rubber-block suspensions that excel off road. Brakes are S-cam drums with air systems that benefit from careful line and chamber inspection. Common tire sizes include 11R22.5 and 11R24.5 on stud-pilot or early hub-pilot wheels, and many trucks retain PTO provisions for wet kits or mixer drives.

For buyers, parts support is a two-lane story. Driveline components are standard North American pieces, so clutches, transmissions, axle parts, brakes, starters, alternators, and engine service items remain readily available. Cab structure, trim, glass, and dash components are more specialized and typically sourced from salvage, reproduction runs, or enthusiast networks. Prioritize frame and cab condition over cosmetics. Look closely for double-frame rust jacking, rail drill-hole cracks, crossmember elongation, spring hanger and torque rod bushing wear, cab mount corrosion, kingpin play, and steering box lash. Verify rear axle ratios, transmission model, and tire rolling radius to ensure the gearing matches your route speeds and terrain.

Pre-emission mechanics are a selling point for simplicity and lower maintenance costs, but plan for higher noise levels, less aerodynamic efficiency, and potential regional compliance limits. California and some metro regions restrict pre-2010 engines for commercial use outside of exemptions like low-mileage agriculture or historic registration, so confirm local rules before purchase. Older VIN formats may not decode in modern systems, so gather engine CPL or arrangement numbers, transmission tags, and axle model tags to support parts lookup and insurance. For working duty, budget for a full fluid service, air system cleanout, wiring repairs, and brake plumbing refresh to baseline reliability, then enjoy the robust build that made Diamond Reo a favorite among vocational fleets.