Iron Profile: Caterpillar 777 Off-Highway Haul Truck

Introduced by Caterpillar in 1974, the 777 became one of the company’s most popular line of off-highway haul trucks. Building on their experience with the 769B and 773 trucks, the 777 continued the successful mechanical-drive haulers into the 85 ton class. This truck featured the 870-flywheel-horsepower D348, V-12 diesel engine, and low weight-to-horsepower ratio. With the seven-speed planetary transmission, this power was put to good use, typically in mining and large earthmoving projects.

The 777 had a newly designed front end, ROPS cab and engine deck. This allowed much easier in-frame servicing by technicians, and was so successful it continues to be the basic design used today. The ride over rough quarry roads was made smooth by four huge oil-pneumatic suspension cylinders. The two front cylinders acted as steering kingpins for a short turning radius in tight loading spots. The 777 could make a clearance turning circle in 88 feet.

The Cat 777 body had the same familiar features that proved so reliable and durable on the 769B and 773 trucks: dual-sloped dump bed designed for retaining heaped loads up steep inclines, wrap-around ribs for added strength, steel corner castings and rolled steel toprail sections to reinforce critical stress areas, and a low loading height. The ten box-sectioned ribs also had the unique feature of funneling engine exhaust to heat the bed for easier dumping of sticky materials in cold weather.

So successful was this haul truck it found itself developed by Caterpillar into an off-highway tractor called the 776. This powerful tractor proved versatile enough to become popular in variations modified to suit a wide spectrum of needs. High-capacity dump bodies, coal haulers, and heavy equipment trailers—all have seen use.

The 777 series truck has continued over the years to its current version, the 777G, with new advances in technology refining its weight class. For almost three decades this hauler has proven itself one of Caterpillar’s most durable and successful trucks.
 

SPECIFICATIONS:
Horsepower, flywheel — 870 (649 kW)
Total empty weight —122,600 lb. (55,610 kg)
Loaded weight to Hp ratio (with standard options) — 336:1
Capacity, tons — 85 (77t)
Cubic yards, struck (SAE) — 47.5 (36 m³)
Cubic yards, heaped 2:1 (SAE) — 67.1 (51 m³)
Transmission — 7 range automatic power shift with 1 reverse range.
Top speed loaded — 33 MPH (53 km/h)