Case CX300D Excavator: 30-Ton D-Series Tier 4 Final Production Machine
The Case CX300D is a 30-ton class D-Series hydraulic excavator built around a Tier 4 Final diesel, electrohydraulic precision controls, and a modern operator station. It sits between the CX300C and the CX300E in Case's full-size excavator lineup and remains a workhorse on production sites today.
Where the CX300D fits in the Case excavator line
The CX300D is a 30-ton class D-Series excavator, positioned between the CX300C predecessor and the CX300E successor in Case's full-size excavator lineup. D-Series machines moved the platform to EPA Tier 4 Final emissions with DPF and SCR aftertreatment, brought refined electrohydraulic control valves, and modernized the operator station.
Case CX300D Excavator - Quick Specs
- Class
- 30-Ton Excavator
- Generation
- D-Series
- Engine
- Tier 4 Final Diesel
- Aftertreatment
- DPF + SCR (DEF)
- Drivetrain
- Hydrostatic Dual-Path
- Undercarriage
- Steel Track
- Tail Swing
- Conventional
- Serial Plate
- RH lower cab frame, below windshield
- Predecessor
- CX300C
- Successor
- CX300E
Engine, hydraulics, and drivetrain
The CX300D runs a Tier 4 Final diesel through a hydrostatic dual-path drivetrain into a steel-track undercarriage. The main hydraulic pump - commonly a load-sensing piston pump - drives boom, dipper, bucket, swing, and propel circuits through electrohydraulic control valves. The closed-loop control allows finer modulation than the C-Series predecessor and gives the operator predictable response under variable load.
Tier 4 Final aftertreatment uses a DPF for particulate control combined with an SCR catalyst and DEF dosing for NOx reduction. Cooled EGR is integrated into the engine package. These systems are reliable when fed clean fuel and quality DEF, but service awareness is a real factor in operating cost.
Common service items on the CX300D
- Engine internals: Tier 4 Final diesel pistons, rings, sleeves, head gaskets, bearings. Common-rail injection.
- Aftertreatment: DPF service and regeneration, DEF tank and dosing module, SCR catalyst, EGR cooler service, NOx sensors.
- Fuel system: Common-rail injectors, lift pump, high-pressure pump, primary and secondary filters with tight water-separator standards.
- Cooling system: Radiator, water pump, thermostat, fan, charge-air cooler, hoses, belts.
- Hydraulic system: Boom, dipper, bucket, and swing cylinder seal kits, main pump rebuild, electrohydraulic control valves, hoses and fittings.
- Boom and dipper: Pin and bushing service at every joint, bucket pins, thumb attachment hardware, quick coupler service.
- Undercarriage: Steel track inspection and replacement, rollers, idlers, drive sprockets, recoil springs.
- Swing system: Swing motor and reduction gear, swing bearing inspection, swing brake.
- Electrical / ECU: Engine ECU, instrument cluster, sensors, harness, telematics module on equipped units.
- Cab glass and wiper: KHN16820 24-inch wiper blade, KHN3046 front lower glass, and KHN2632 front upper glass cross-fit across Case and Link-Belt excavators.
- Operator station: Seat, joystick controls, pedal linkage, instrument panel, cab HVAC.
Parts we carry for the Case CX300D
| Category | Common Parts | Browse |
|---|---|---|
| Engine | Tier 4 Final diesel internals - pistons, rings, sleeves, gaskets | Browse Engine |
| Aftertreatment | DPF, SCR, DEF dosing, EGR components, NOx sensors | Browse Aftertreatment |
| Fuel System | Common-rail injectors, HP pump, lift pump, filters | Browse Fuel System |
| Cooling | Radiator, water pump, charge-air cooler, hoses | Browse Cooling |
| Hydraulics | Main pump, swing motor, cylinders, seal kits, valves | Browse Hydraulics |
| Boom / Dipper | Pins, bushings, bucket and quick-coupler hardware | Browse Boom / Dipper |
| Undercarriage | Steel tracks, rollers, idlers, sprockets, recoil springs | Browse Undercarriage |
| Swing | Swing motor, reduction gear, swing bearing, swing brake | Browse Swing |
| Cab Glass / Wiper | KHN16820 wiper, KHN3046 lower glass, KHN2632 upper glass | Browse Cab Glass |
| Electrical / ECU | ECU, sensors, harnesses, instrument cluster | Browse Electrical |
| Operator Station | Seat, joysticks, pedal linkage, gauges, HVAC | Browse Operator Station |
Need a part for your Case CX300D Excavator?
Aftertreatment, common-rail fuel components, main hydraulic pumps, and undercarriage are the highest-value items on a CX300D. Call our parts team with your serial number.
Request a PartWhat to verify before ordering
- Serial number. Confirm the machine serial on the CX300D before ordering year-specific parts.
- Engine serial. Tier 4 Final engine internals must match the engine serial.
- Hydraulic cylinder bore. Cylinder seal kit fit depends on bore dimension - measure before ordering.
- Tier 4 emissions revision. DPF and DEF/SCR components saw revisions during production - confirm by serial.
- Engine ECU calibration. Common-rail injectors and ECU sensors are calibrated to specific build years.
- Bucket and quick coupler. Quick-coupler interface varies - confirm before ordering attachment-side hardware.
- Undercarriage configuration. Standard and long-undercarriage variants exist - track shoe width and chain pitch must match.
Why the CX300D still earns a paycheck
The Case CX300D is a 30-ton class production excavator suited to general site work, utility installation, residential and commercial earthmoving, and mining and quarry work depending on configuration. It runs a proven Tier 4 Final diesel, a load-sensing piston pump, and a steel-track undercarriage that holds up under sustained production.
Maintenance priorities on a CX300D: clean fuel and tight water separation for common-rail injection, DPF regen behavior tracking, hydraulic oil condition, swing-bearing lubrication, steel-track tension and undercarriage wear monitoring, and pin / bushing service at every joint. Broken Tractor maintains parts coverage across the Case excavator family.
