Cat 740C EJ vs 745C: discharge, payload and axle weights

Choose the discharge system before comparing the C-series payload

The 740C EJ pushes its load out horizontally; the 745C raises its dump body. The ejector's front-to-back blade is driven by a purpose-built, four-stage double-acting cylinder. This changes the unloading envelope as well as the available capacity.

Where overhead room is restricted, an ejector can discharge without elevating the whole body. Site clearances and operating procedures still govern the actual task.

Material size places a specific limit on that choice. Caterpillar's 740C EJ brochure describes an application with rocks smaller than six inches for durability and wear life. A body lined with hardened plate is therefore not a promise that oversized rock suits the ejector mechanism.

Examine the intended material along with the floor, sidewalls and upper rails. The moving blade and horizontal cylinder create inspection points that a conventional tipper body does not have.

The 745C's optional scissor tailgate changes body volume figures. Its brochure lists tailgate-equipped struck and heaped capacities separately from the open-body figures. Those are volume conditions, not permission to exceed rated payload.

Dense material can reach the weight limit before the largest heaped volume is filled. An exhaust-heated body and body liners are also options, so an advertisement's photographs need to establish which arrangement the capacity refers to.

Axle weights need their load state attached. Empty weight, the payload apportioned to an axle and the complete loaded axle weight are three different rows. The earlier table mixed payload entries into loaded-axle cells and attached percent signs to mass figures.

Corrected entries now keep those categories separate. In the 745C source, the front axle's rated-load metric and imperial pair is itself inconsistent; that printed pair remains qualified, rather than being used as a new allowable axle load.

Both C-series publications describe automatic differential-lock control and automatic retarding, but those functions do different jobs. Wheel-speed information governs the traction system, which releases its clutches when conditions permit. The retarder can apply engine compression braking to control descent.

Waiting Brake is another function: it holds service brakes during a stop without repeated parking-brake use. A brake indication during one of these intended actions needs its operating state recorded before a fault is inferred.