Description

Komatsu HD320-3, HD325-3 Operators Manual

You’ve got a Komatsu HD320-3 or HD325-3 dump truck on the job, and the operator’s manual that came with it is either missing, dog-eared, or living under a seat soaked in hydraulic oil. I’ve seen crews try to run these rigs with a photocopy of a photocopy, or worse, a generic aftermarket booklet that says “check fluid levels” without telling you which dipstick or what grade. That’s how you eat a final drive. This manual is the real thing — 159 pages of factory Komatsu documentation, scanned from the original print. It covers the HD320-3 (serial numbers 2501 and up) and the HD325-3 (serial numbers 1501 and up). If you’re going to keep one of these trucks moving, you need Komatsu HD320-3, HD325-3 Operators Manual on your bench, not a PDF from some forum.

Safety Hints: Not Just a Sticker

Page 4 of this manual starts with “Safety Hints.” That’s a full section, not a paragraph. It covers the specific hazards of operating a 30-ton dump truck — loading, dumping, slope work, and visibility. I’ve seen too many operators skip reading this section because they think they know how to drive a truck. Then they dump a load with the body still raised into power lines. The manual doesn’t assume you’re stupid. It assumes you’re busy and need the facts. The instructions are clear: where to stand, what to lock out, and when to use the parking brake. If you’re training a new hand, make them read this section aloud before they touch the starter.

Check Before Starting – The 42-Page Routine

From page 42, the “Check Before Starting” section walks you through every gauge, fluid level, and belt tension point. The manual lists the exact locations of the engine oil dipstick, transmission dipstick, and hydraulic tank sight glass. It also tells you what the water temperature and oil pressure gauges should read at idle before you move the truck. That’s the kind of detail that prevents a cold start with cold oil and a turbo that’s starved for lube. The break-in procedure on page 3 says to idle until the gauges hit the green range. That’s not a suggestion. The manual also includes the service meter reading — 100 hours for break-in. If you’re running a fleet, you need this data to set your PM schedules.

Periodic Maintenance: 50 to 4000 Hour Intervals

The maintenance table starts on page 88 and breaks down every 50, 250, 500, 1000, 2000, and 4000 hour service. Each interval lists the specific checks: at 50 hours, grease the steering linkage and check the tire pressure. At 250 hours, replace the engine oil and filter. The manual doesn’t just say “change oil” — it gives the capacity (in quarts) and the API classification. The “Precautions for Maintenance” section on page 82 reminds you to block the wheels before crawling under the truck. I’ve seen a 40-ton truck roll off a jack because somebody skipped that step. The OEM torque values for the wheel nuts? Page 73. Don’t guess. Every 2000 hours, the manual calls for checking the injector adjustment screws and retorquing the mounting bolts. That’s the kind of work you do with a torque wrench, not a calibrated arm.

Troubleshooting Guide: When the Truck Won’t Move

The “Trouble Shooting Guide” section is a quick-reference list of problems and what to check. Engine won’t start? Fuel system, battery, starter. Transmission won’t engage? Check the shift linkage and the neutral safety switch. The manual doesn’t waste space with theory. It tells you the most likely cause and the next step. If you’re dealing with a Manual Transmission issue, the guide covers the specific symptoms of a slipping clutch or a worn synchro. For the Manual Transmission in the HD320-3, the manual includes the proper clutch adjustment procedure. That’s information you won’t find in a generic repair book. It’s Komatsu-specific, written by the engineers who built the truck.

Cold Weather Operation and Storage

If you operate in winter conditions, the “Cold Weather Operation” section is gold. It tells you the correct coolant mixture for temperatures down to -30°F, the battery cold-cranking amp requirement, and the fuel grade to prevent gelling. The storage section covers how to park the truck for more than 30 days — battery disconnect, fluid levels, tire capping, and what to grease. The manual also includes a section on “Break-In Your New Machine” (page 3) that stresses the 100-hour gentle operation period. Skip that, and you’ll burn oil for the rest of the engine’s life.

Source Authenticity: OEM vs Aftermarket

This is an original Komatsu publication, not a third-party reprint. The document file name ends with “en-35331010492.pdf” — that’s a Komatsu part number. The cover says “Operation & Maintenance Manual” and “KOMATSU” in bold. The TOC matches the official Komatsu structure: Safety Hints, General Locations, Operator’s Compartment, Instruments and Controls, Check Before Starting, Operating Your Machine, Periodic Maintenance, Adjustment, Wear Parts, Troubleshooting, Specifications, and Fuel & Lubricants. Aftermarket manuals often cut corners, skip the full safety section, or use generic torque values. This one has the OEM specs for the SAE 10W-30 engine oil, the hydraulic oil filter part number, and the tire pressure for the 18.00-25 tires. You can’t get that from a Haynes book.

Related Manuals

• Komatsu WH609-1E0 – WH716-1E0 Operators Manual | 272 Pages OEM
• Komatsu WD900-3 2004 Operators Manual – Factory OEM Specs
• Komatsu WB146-5 WB146PS-5 2006 Operators Manual – OEM Safety & Maintenance

Does this manual cover the HD325-3 dump truck with the aftertreatment system?

No. This manual is for the HD320-3 and HD325-3 models without the aftertreatment. It covers the standard Komatsu SA6D170 engine and the Allison transmission. If your truck has a DPF or SCR, you need the later manual.

Can I print this PDF and keep it in the cab?

Yes. The file is a high-resolution scan. 159 pages.

This is the manual your truck came with from the factory. It tells you the break-in procedure, the maintenance schedule, the torque specs, and the safety steps that keep you alive. If you’re running a Komatsu HD320-3 or HD325-3, stop guessing. Access the Factory Manual from AutoRepairManuals and put it on your tablet or print it out. Your machine, your crew, and your wallet will thank you.