UD TRUCKS NISSAN DIESEL BIG THUMB RESONA CW CD CK CV PF6 PF6T PF6-T 12.5L TURBO DIESEL 26T DRIVE GEAR ENGINE COOLING WATER PUMP ASSY (OE: 21010-96226 / 2101096226 / 21010-96225 / 21010-96227 / 21010-96265 / 21010-96266 / 21010-96268 / 21010-96269 / GWN-60A)

Overview

The UD Trucks / Nissan Diesel Big Thumb PF6T 26T Gear-Driven Engine Water Pump Assembly (Water Pump Assy 21010-96226 / 2101096226 / 21010-96225 / 21010-96268 / GWN-60A) is a commercial-grade engine cooling system component engineered specifically for UD Trucks and Nissan Diesel heavy commercial transport trucks, prime movers, and multi-axle tippers powered by Nissan Diesel PF6 (12.5L naturally aspirated) and PF6T / PF6-TA / PF6-TB (12.5L turbocharged) 6-cylinder direct-injection diesel engines (UD Big Thumb, Resona, CW, CD, CK, CV, and CG series heavy prime movers, logging trucks, cargo lorries, dump trucks, and concrete mixers). Built with a precision-machined 26-tooth (26T) drive gear, rigid cast iron volute housing, precision-machined multi-bolt perimeter mounting base, and dynamically balanced high-flow internal impeller, this gear-driven water pump delivers continuous, pressurized coolant circulation through the massive 12.5L engine block, cylinder head, and oil cooler. Replacing a worn, noisy, bearing-seized, or leaking water pump restores optimal cooling efficiency and prevents catastrophic engine overheating under sustained commercial transport and heavy-load hauling.

Key Dimensions & Specifications

• Drive Mechanism: Precision-machined 26-tooth (26T) drive gear engineered for direct, smooth engagement with the engine timing gear train.

• Heavy-Duty Cast Iron Housing: Thick-walled volute casing built to withstand extreme vibration, heavy radial gear loads, and high engine operating temperatures.

• Mounting Base Configuration: Multi-bolt perimeter mounting flange base with a flat CNC-machined rear sealing surface for direct installation onto the engine timing case / front block cavity.

• Bearing & Mechanical Shaft Seal: Industrial-grade high-capacity sealed roller/ball bearing cartridge paired with a wear-resistant silicon-carbide/carbon mechanical shaft seal to resist shaft play and coolant weepage under continuous load.

• Coolant Flow Impeller: High-efficiency cast internal impeller designed for continuous, high-volume coolant displacement across the 12.5L inline-6 cylinder block and oil cooler.

• Please count your drive gear teeth (26T) and verify your existing water pump mounting pattern against your old sample pump before ordering.

Compatible Truck Models & Engine Applications

• UD TRUCKS / NISSAN DIESEL COMMERCIAL TRUCKS & PRIME MOVERS:

  • Big Thumb Heavy Truck Series (CW, CD, CK, CV, CG Heavy Prime Movers, Heavy Cargo Lorries, Multi-Axle Tippers, Dump Trucks & Concrete Mixers)

  • Resona Heavy Commercial Series (Late-model PF6 transitions)

• Engine Application:

  • Nissan Diesel / UD PF6 (12.5L / 12,503cc Inline-6 Naturally Aspirated Direct Injection Diesel)

  • Nissan Diesel / UD PF6T / PF6-T / PF6-TA / PF6-TB (12.5L / 12,503cc Inline-6 Turbocharged & Intercooled Diesel)

• OEM & Cross-Reference Part Numbers:

  • 21010-96226 / 2101096226 (Nissan Diesel / UD Genuine OEM)

  • 21010-96225 / 2101096225

  • 21010-96227 / 2101096227

  • 21010-96265 / 2101096265

  • 21010-96266 / 2101096266

  • 21010-96267 / 2101096267

  • 21010-96268 / 2101096268

  • 21010-96269 / 2101096269

  • GMB: GWN-60A / GWN60A

  • PARAUT / ASAHI: A-2032 / A2032

• (Note: Nissan Diesel heavy engines feature different timing drive gear setups: older PE6T models typically utilize a 20T gear [21010-96172], whereas PF6 / PF6T engines utilize this 26T drive gear pump [21010-96226 / GWN-60A]. Always count the gear teeth [26T] and compare against your old sample pump prior to ordering.)

Why Choose Our Commercial Truck Parts?

• Induction-Hardened 26T Drive Gear: Heat-treated gear teeth resist pitting, surface fatigue, and gear backlash, ensuring smooth, quiet timing gear mesh under high torque.

• High-Volume 12.5L Coolant Flow: Precision-cast impeller delivers steady, pressurized circulation across both the cylinder block and oil cooler, eliminating hot spots under heavy turbo boost and pulling loads.

• High-Capacity Bearing & Mechanical Seal: Sealed heavy-duty bearing cartridge paired with a premium silicon-carbide mechanical seal withstands continuous gear-driven radial forces without developing shaft wobble or weeping.

• Precision CNC-Machined Mounting Flange: Flat-machined sealing surface ensures a secure, leak-free gasket installation directly onto the engine block.

• Ready Stock & Fast Shipping: Readily stocked for quick dispatch.

Need Help Confirming Fitment?

Unsure whether this 26T water pump matches your UD truck's existing PF6 or PF6T engine setup?

• Check your old pump against the 26T drive gear, mounting base pattern, and housing profile.

• Or send your Chassis Number (VIN) / Engine Model (PF6 / PF6T) / Gear Teeth Count (26T) / sample photos to our team via WhatsApp for instant confirmation!