145-4878 CAT D11R Variable Displacement Piston Pump

Product Overview

The 145-4878 is a Caterpillar hydraulic pump assembly specified in the Cat Parts Store for the D11R Track-Type Tractor. Caterpillar identifies the unit as an Axial Piston Pump, Variable Displacement. The same official listing identifies 10R-0555 as the corresponding Cat Reman Axial Piston Pump Variable Displacement.

The variable-displacement axial piston architecture is intended for demanding mobile hydraulic applications where pump output must respond to changing system requirements.

For aftermarket replacement, the critical engineering requirement is not simply matching the machine model. The replacement pump should be verified against the complete 145-4878 part-number configuration, installation geometry, drive connection, hydraulic ports and operating requirements.

Our replacement approach focuses on interchangeability, dimensional consistency, hydraulic performance and 100% simulated-condition testing before shipment.

Caterpillar also notes that a factory-fit indication does not guarantee compatibility after machine configuration changes. Therefore, the original part number and machine configuration should always be verified before purchase and installation.

Part Number Identification

• CAT OEM Part Number: 145-4878
• Part Number: 1454878
• Cat Reman Number: 10R-0555
• Machine: Caterpillar D11R Track-Type Tractor
• Pump Type: Variable Displacement Axial Piston Pump

Technical Specifications

Data verification notice: Caterpillar’s currently accessible public Parts Store listing confirms the pump type, dimensions and D11R compatibility, but it does not publish the complete engineering data for this specific pump assembly. Therefore, displacement, rated pressure, peak pressure, maximum speed, control configuration and weight are intentionally not presented as verified values.

• Brand: Caterpillar / CAT
• Part Number: 145-4878
• Part Number without hyphens: 1454878
• Cat Reman Reference: 10R-0555
• Product Type: Variable Displacement Axial Piston Pump
• Machine Application: Caterpillar D11R Track-Type Tractor
• Pump Architecture: Axial Piston, Variable Displacement
• Official Published Length: 15.55 in
• Official Published Height: 9.6 in
• Official Published Width: Not stated on the current public Cat listing
• Displacement: Not published on the current public Cat listing
• Rated Pressure: Not published on the current public Cat listing
• Peak Pressure: Not published on the current public Cat listing
• Maximum Speed: Not published on the current public Cat listing
• Control Type: Variable displacement is confirmed; the detailed controller configuration is not published on the current public Cat listing
• Weight: Not published on the current public Cat listing
• Compatible Model: D11R
• OEM Listing Status: 145-4878 PUMP GP; 10R-0555 PUMP GP-HYD / Cat Reman

This approach deliberately avoids using unverified third-party specifications as OEM data.

Key Technical Advantages

1. Variable Displacement Axial Piston Design

Caterpillar officially classifies 145-4878 as a Variable Displacement Axial Piston Pump.

This architecture allows the pump displacement to respond to hydraulic demand, making it suitable for heavy mobile machinery with continuously changing load conditions.

2. Heavy-Duty D11R Application

The official Cat Parts Store identifies D11R as the compatible Track-Type Tractor for 145-4878.

A pump operating in this environment must tolerate high mechanical loading, repetitive hydraulic cycles and substantial thermal stress. Replacement quality therefore depends on hydraulic performance as well as mechanical interchangeability.

3. Direct Part-Number Traceability

The 145-4878 part number provides a direct reference to Caterpillar’s official parts catalog, while 10R-0555 is identified as the corresponding Cat Reman variable-displacement axial piston pump.

This traceability reduces the risk of selecting a visually similar but hydraulically incompatible pump.

4. Engineering-Focused Interchangeability

For a successful replacement, engineers should verify:

• Mounting flange dimensions
• Drive-shaft and coupling configuration
• Hydraulic port locations
• Housing dimensions
• Control configuration
• Rotating-group compatibility
• Operating pressure and flow requirements

Our replacement strategy therefore treats 145-4878 as a complete engineering identifier rather than relying on the generic term “D11R hydraulic pump.”

5. Precision Manufacturing of the Rotating Group

Axial piston pump performance depends heavily on the geometry and surface condition of the rotating group, including the cylinder block, pistons, slippers and valve plate.

Critical manufacturing controls include:

• Rotating-group dimensional accuracy
• Cylinder-block and valve-plate contact quality
• Piston/slipper geometry
• Shaft and bearing fit
• Sealing-surface condition
• Internal leakage control

These factors directly affect volumetric performance, operating temperature and service reliability.

Application Areas

Caterpillar’s official listing identifies the D11R Track-Type Tractor as the compatible machine for 145-4878.

Typical target applications therefore include:

• Caterpillar D11R Track-Type Tractors
• D11R Bulldozer Hydraulic Systems
• Heavy-Duty Track-Type Construction Equipment
• Mining and Earthmoving Machinery
• Large Earthmoving Operations
• Heavy-Duty Mobile Hydraulic Systems

Compatibility with other D11-series machines should not be assumed solely from the machine family. The actual machine serial number, original pump part number and hydraulic configuration should be checked.

Expert Maintenance Tips

1. Verify the Complete Part Number

Before installation, confirm the original identification as:

145-4878

Also verify the 10R-0555 Reman cross-reference where applicable. Caterpillar explicitly recommends checking the machine’s current configuration before purchase.

2. Verify Installation Dimensions

Caterpillar’s public listing gives the following dimensions for 145-4878:

• Length: 15.55 in
• Height: 9.6 in

These dimensions should be checked against the existing pump and available installation space.

3. Inspect the Drive Connection

Before installing a replacement pump, inspect:

• Coupling condition
• Shaft spline condition
• Shaft-end wear
• Alignment
• Torsional wear

A worn coupling or drive component can cause premature failure even when the replacement pump itself is correctly manufactured.

4. Keep the Hydraulic Circuit Clean

Flush and inspect the hydraulic circuit before commissioning the replacement unit. Remove contamination caused by previous pump wear and verify the condition of the filtration system.

Axial piston components operate with controlled internal clearances, making contamination control essential for stable performance.

5. Commission the Pump Gradually

During initial commissioning, verify:

• Oil level
• Suction condition
• Rotation direction
• Air removal
• Abnormal noise
• External leakage
• Initial temperature

Avoid immediately subjecting a newly installed pump to prolonged full-load operation.

6. Perform 100% Simulated-Condition Testing

For professionally manufactured replacement units, recommended testing includes:

• Rotation testing
• Leakage inspection
• Flow-response verification
• Pressure-response verification
• Variable-displacement response testing
• Continuous running testing
• Thermal stability testing
• Abnormal-noise inspection

This provides a stronger basis for verifying replacement reliability than a simple no-load functional test.

OEM Reference & Verification Note

Primary technical reference: Caterpillar official Parts Store listing for 145-4878, which confirms:

• Cat brand
• 145-4878 pump group
• Variable displacement axial piston pump
• D11R Track-Type Tractor compatibility
• 15.55 in length
• 9.6 in height
• 10R-0555 Cat Reman cross-reference