Hawk 31 HP Gearbox — PXI/XXT Series

The Hawk 31 HP reduction gearbox (code 1.904-903.0) is a heavy-duty gear reduction box manufactured by Leuco S.p.A. for Hawk high-pressure pumps. It converts the higher RPM output of petrol engines down to the operating speed required by Hawk PXI and XXT series piston pumps, delivering up to 23 kW (31 HP) of transmitted power through a robust 2.176:1 reduction ratio. With an SAE J609B engine flange and a 24 mm pump shaft, this gearbox provides a direct, bolt-on connection between your engine and pump — no belts, no alignment hassles.

Specifications

Code	1.904-903.0
Max Power	23 kW (31 HP)
Input Speed	3,150 RPM
Output Speed	1,450 RPM
Gear Ratio	2.176:1
Engine Shaft	1-1/8″ (28.6 mm)
Pump Shaft	24 mm
Engine Flange	SAE J609B
Oil	SAE 90 — 0.33 L (11 oz)
Weight	4 kg
Spare Parts Kit	1.905-008.0

Applications

• Petrol-engine-driven portable pressure washers up to 31 HP
• Industrial and commercial cleaning rigs using Hawk PXI 350, PXI 500, or PXI Heavy Duty pumps
• Vehicle-mounted wash systems with Hawk XXT series pumps (up to 200 bar / 70 L/min)
• Municipal cleaning trucks and mobile blasting units
• Misting, dust suppression, and fire-fighting pump sets

Key Features

• 2.176:1 reduction ratio — converts 3,150 RPM engine speed to the 1,450 RPM that PXI and XXT pumps require
• 23 kW (31 HP) capacity — the highest-rated gearbox in the Hawk range for petrol-engine applications
• SAE J609B flange — direct bolt-on fitment to a wide range of petrol engines (Honda, Vanguard, Kohler, etc.)
• Compact & lightweight — only 4 kg, ideal for portable and vehicle-mounted rigs
• Low maintenance — simple SAE 90 gear oil fill (0.33 L); no external lubrication system needed
• Genuine Hawk/Leuco quality — hardened steel gears for long service life under demanding conditions

Technical Documents

• Hawk NMT/XLTI/PXI Gearbox – Parts Schematic (PDF)

Parts & Service

AES Waterblasters stocks genuine Hawk gearbox spare parts including the rebuild kit (code 1.905-008.0) with bearings, seals, and gaskets. We can also supply complete replacement gearboxes and advise on engine-to-pump matching. For parts enquiries or technical support, phone 09 271 4782.

Related Models

• Hawk 24 HP XLTI Gearbox — 17.7 kW model for XLTI, PXI, and XXT pumps
• Hawk 13 kW NMT Gearbox — 13 kW model for NMT and NPM series pumps
• Hawk 55 kW Gearbox — heavy-duty gearbox for high-power electric motor applications