Replacement AAA Triplex Pressure Washer Pump, 4000Psi, 3.5GPM

Replacement AAA Triplex Pressure Washer Pump, 4000Psi, 3.5GPM

The 90039 Replacement AAA Triplex Pressure Washer Pump is a commercial-grade, high-performance pump engineered for long service life and maximum cleaning power. Designed as a direct replacement for many 4000 PSI pressure washers, it delivers a reliable 3.5 GPM flow using an efficient oil-bath crankcase and precision-machined triplex plungers. Its PowerBoost™ technology optimizes pressure at the nozzle for stronger cleaning impact while reducing internal stress on the pump.

Country of Origin: USA

Key Features / Specifications

Part number: 90039
Pump type: Triplex plunger pump
Max pressure: 4000 PSI
Flow rate: 3.5 GPM
Engine flange: SAE standard (fits most 1” shaft engines)
PowerBoost™ technology: Produces higher pressure at the nozzle while reducing pump load
Manifold material: Anodized die-cast aluminum for corrosion resistance
Plungers: Hardened stainless steel with ceramic coating
Thermal relief protection: Automatically prevents overheating during bypass
Oil bath crankcase: Allows cooler operation and extended pump life
Integrated unloader: Fully adjustable for precise pressure control
Mounting: Horizontal installation, standard bolt pattern
Inlet/outlet: 3/8" QC outlet, 3/4" garden hose inlet (may vary depending on included fittings)

Kit Includes:

• (1) AAA 90039 Triplex Pressure Washer Pump assembly
• Pre-installed thermal relief valve
• Pre-installed adjustable unloader
• Inlet filter / garden hose adapter (varies by kit)
• Owner’s manual and setup guide

Ideal For:

• Replacing worn or failed pumps on 4000 PSI gas-powered pressure washers
• Contractors seeking a durable, commercial-grade triplex pump with long service life
• Homeowners upgrading from OEM axial pumps to a higher-performance triplex design
• Pressure washing decks, siding, driveways, farm equipment, and heavy-duty cleaning tasks