Machine models
Komatsu HM300-3 and HM400-3 specifications
HM300-3 traction control and body geometry
On the European HM300-3, wheel-speed sensors trigger the inter-axle differential lock when slip begins. Continued slipping brings brake intervention at the affected wheel. KTCS therefore involves both driveline locking and selective braking; a six-wheel-drive description alone does not explain how this truck manages a slippery haul road.
The body drawing separates loading height from raised-body clearance. Its 2,830 mm loading edge helps establish whether a loading machine can clear the side; the 6,440 mm raised height matters beneath overhead structures. Neither figure is ground clearance.
Komatsu also shows a 70-degree body angle, distinct from the 45-degree articulation angle used for steering.
The HM300's front and centre wet-disc brakes also provide retardation. The service schedule combines torque-converter, transmission and retarder cooling oil in one refill entry. That quantity should not be mistaken for coolant.
For access to the engine and transmission, the cab tilts rearward; this is a maintenance arrangement, not another suspension setting.
Source: Komatsu HM300-3 European brochure, traction, service and dimension sections.HM400-3 engine edition and load distribution
Komatsu's European HM400-3 brochure identifies the SAA6D140E-6 and EU Stage IIIB engine, with separate gross and net ratings. The older E-5 engine name and 338/334 figures in the reference column do not describe that European configuration. Treating those kilowatt-sized entries as horsepower would substantially understate output.
The corrected column identifies its edition instead of combining both packages into a fictional truck.
Body capacity presents a second unit problem. The HM400's 18.2 struck and 24.0 heaped quantities are cubic metres in the manufacturer's schedule. Payload is tonnes.
A full body and the payload limit are different constraints, particularly when loading dense material.
The manufacturer's empty and loaded axle percentages differ markedly: load moves toward the tandem as the body fills. Total machine weight alone therefore cannot establish individual axle loading. Its dimensional drawing is explicitly based on 29.5 R25 tyres, while the HM300 drawing uses a smaller tyre installation.
These are complete machine arrangements, not interchangeable body dimensions.
Source: Komatsu HM400-3 European brochure, engine, body, weight and tyre conditions.| Listing-entry count |
|---|
| 2 |
| Publisher name | Source guide | Listing-entry count | Labels named by the source |
|---|---|---|---|
| Komatsu | HM300-3 and HM400-3 | 2 | HM300-3 and HM400-3 |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Overall Length | 10275 mm / 33.71 ft (European brochure) | 36.44 ft |
| Overall Width | 2900 mm / 9.51 ft (European brochure, 23.5 R25 tyres) | 11.32 ft |
| Overall Height | 3510 mm / 11.52 ft cab; 6440 mm / 21.13 ft with body raised | 12.26 ft |
| Wheelbase | 4100 mm / 13.45 ft front-to-centre axle; 1710 mm rear tandem spacing | 4350 mm / 14.27 ft front-to-centre axle; 1970 mm rear tandem spacing |
| Ground Clearance | 572 mm / 1.88 ft under lowered rear body; 575 mm at articulation joint | 2.33 ft |
| Dump Ground Clearance | 572 mm / 1.88 ft rear body-lip clearance in lowered drawing position | 808 mm / 2.65 ft rear body-lip clearance in lowered drawing position |
| Specification | HM300-3 |
|---|---|
| Dump Height | 2830 mm / 9.28 ft loading edge; 6440 mm raised body height |
| Specification | HM300-3 |
|---|---|
| Dump Angle | 70 degrees body raise; 45 degrees steering articulation each side |
| Lower Time | 10.5 sec |
| Raise Time | 10.5 sec |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Rated Payload | 28 metric tonnes / 30.9 US short tons | 40 metric tonnes / 44.1 US short tons |
| Capacity - Struck | 17.5 yd3 | 18.2 m3 / 23.8 yd3 |
| Capacity - Heaped | 22.4 yd3 | 24.0 m3 / 31.4 yd3 (2:1 SAE) |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Number Of Cylinders | 6 | 6 |
| Engine Model | Komatsu SAA6D125E-6 | Komatsu SAA6D140E-6 (European EU Stage IIIB configuration) |
| Gross Power | 332 hp | 473 hp / 353 kW (ISO 14396, European brochure) |
| Net Power | 324 hp | 469 hp / 350 kW (ISO 9249, European brochure) |
| Power Measured @ | 2,000 rpm | 2,000 rpm |
| Displacement | 11.04 L / 673.7 cu in | 15.24 L / 930.0 cu in (European brochure) |
| Specification | HM300-3 |
|---|---|
| Max Torque | 1,239 lb-ft |
| Aspiration | Komatsu Variable turbo charge |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Fuel Capacity | 102.6 gal |
|
| Tire Size | 23.5 R25 | 29.5R25 |
| Specification | HM300-3 |
|---|---|
| Hydraulic System Fluid Capacity | 27.2 gal |
| Cooling System Fluid Capacity | 98 L / 25.9 US gal is transmission/converter/retarder-cooling oil, not engine coolant |
| Engine Oil Capacity | 9.2 gal |
| Transmission Fluid Capacity | 25.9 gal |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Transmission Type | Auto | Auto |
| Number Of Forward Gears | 6 | 6 |
| Number Of Reverse Gears | 2 | 2 |
| Max Speed | 36.4 mph | 55.9 km/h / 34.7 mph (European brochure) |
| Specification | HM300-3 | HM400-3 |
|---|---|---|
| Total Empty | 54,917 lb | 33660 kg / 74207 lb (European brochure approximate weight) |
| Total Loaded | 116,823 lb | 73740 kg / 162569 lb (European brochure approximate GVW) |
| Source guide | Differing-field count reported |
|---|---|
| HM300-3 and HM400-3 | 28 |
| Figure | HM300-3 | HM400-3 |
|---|---|---|
| Engine horsepower per 1,000 lb of weight | 5.9 | 6.3 hp per 1000 lb, using469hp net and74207lb empty European configuration |
| Fuel tank per engine horsepower | 0.32 gal | 0.29 US gal per net hp (European configuration) |
| Rated payload per cubic yard of heaped body | 2759 lb per yd3 (61800lb /22.4yd3 nominal payload/body) | 2809 lb per yd3 (88200lb /31.4yd3 nominal payload/body) |
| Equipment group | articulated dump truck |
|---|
HM300-3 and HM400-3: owner reports
Related account: “Stuck in low gear, controller errors and transmission rebuild effort”: Hm300-1 to HM400-2.
| Forum index | Equipment class queried | Names in the search | Matching titles |
|---|---|---|---|
| Heavy Equipment Forums | articulated dump truck | Komatsu and the HM300 line that the HM300-3, HM400-3 belongs to (no title names the exact model). That is too few titles to say what owners mostly ask about, so the most recent are listed instead | 4 |
- Komatsu Hm 300 2 Articulated Truck With Codes (Heavy Equipment Forums, 2026-07-30)
- Komatsu Hm300 2 (Heavy Equipment Forums, 2017-05-31)
| Observation date | Listing source | Equipment search | Listings |
|---|---|---|---|
| 2026-09-24 | MachineryTrader | Komatsu articulated dump truck | 30 |
| Model | Listed | Model years | Lowest asking | Highest asking | Median asking | Median hours |
|---|---|---|---|---|---|---|
| HM300-3 | 8 | 2012 to 2015 | $79,500 | $173,715 | $143,013 | 8,628 |
| HM400-3 | 22 | 2012 to 2020 | $50,000 | $321,500 | $115,000 | 13,011 |
| Search date | Database | Names queried | Search result |
|---|---|---|---|
| 2026-09-24 | U.S. Consumer Product Safety Commission | Komatsu together with the articulated dump truck HM300-3, HM400-3 | No matching recall in this search |
| Evidence class | Document, classification and recorded date |
|---|---|
| Reference site |
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| Reference site |
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| Forum threads |
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| Used-market listings |
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| Federal agency data |
|
| Observation field | Recorded value |
|---|---|
| Title count | 4 |
| Forum indexes | Heavy Equipment Forums |
| Search wording | the HM300-3 and HM400-3 articulated dump truck |
| Latest title quoted by the reference | Komatsu Hm 300 2 Articulated Truck With Codes |
| Model and field | Earlier entry | Documented replacement |
|---|---|---|
| HM300-3 Overall Length | 33.8 ft | 10275 mm / 33.71 ft (European brochure) |
| HM300-3 Overall Width | 11.6 ft | 2900 mm / 9.51 ft (European brochure, 23.5 R25 tyres) |
| HM300-3 Overall Height | 21.4 ft | 3510 mm / 11.52 ft cab; 6440 mm / 21.13 ft with body raised |
| HM300-3 Wheelbase | 7.6 ft | 4100 mm / 13.45 ft front-to-centre axle; 1710 mm rear tandem spacing |
| HM400-3 Wheelbase | 9.72 ft | 4350 mm / 14.27 ft front-to-centre axle; 1970 mm rear tandem spacing |
| HM300-3 Ground Clearance | 9.6 ft | 572 mm / 1.88 ft under lowered rear body; 575 mm at articulation joint |
| HM300-3 Dump Ground Clearance | 5.7 ft | 572 mm / 1.88 ft rear body-lip clearance in lowered drawing position |
| HM400-3 Dump Ground Clearance | 28.88 ft | 808 mm / 2.65 ft rear body-lip clearance in lowered drawing position |
| HM300-3 Dump Height | 9.31 ft | 2830 mm / 9.28 ft loading edge; 6440 mm raised body height |
| HM300-3 Dump Angle | 45 degrees | 70 degrees body raise; 45 degrees steering articulation each side |
| HM300-3 Rated Payload | 30.9 lb | 28 metric tonnes / 30.9 US short tons |
| HM400-3 Rated Payload | 40 lb | 40 metric tonnes / 44.1 US short tons |
| HM400-3 Capacity - Struck | 18.2 yd3 | 18.2 m3 / 23.8 yd3 |
| HM400-3 Capacity - Heaped | 24 yd3 | 24.0 m3 / 31.4 yd3 (2:1 SAE) |
| HM400-3 Engine Model | Komatsu SAA6D140E-5 | Komatsu SAA6D140E-6 (European EU Stage IIIB configuration) |
| HM400-3 Gross Power | 338 hp | 473 hp / 353 kW (ISO 14396, European brochure) |
| HM400-3 Net Power | 334 hp | 469 hp / 350 kW (ISO 9249, European brochure) |
| HM300-3 Displacement | 11.1 cu in | 11.04 L / 673.7 cu in |
| HM400-3 Displacement | 15.3 cu in | 15.24 L / 930.0 cu in (European brochure) |
| HM400-3 Fuel Capacity | 518 gal |
|
| HM300-3 Cooling System Fluid Capacity | 25.9 gal | 98 L / 25.9 US gal is transmission/converter/retarder-cooling oil, not engine coolant |
| HM400-3 Max Speed | 58.5 mph | 55.9 km/h / 34.7 mph (European brochure) |
| HM400-3 Total Empty | 43 lb | 33660 kg / 74207 lb (European brochure approximate weight) |
| HM400-3 Total Loaded | 71 lb | 73740 kg / 162569 lb (European brochure approximate GVW) |
| HM400-3 Engine horsepower per 1,000 lb of weight | 7,767.4 | 6.3 hp per 1000 lb, using469hp net and74207lb empty European configuration |
| HM400-3 Fuel tank per engine horsepower | 1.55 gal | 0.29 US gal per net hp (European configuration) |
| HM300-3 Rated payload per cubic yard of heaped body | 1 lb | 2759 lb per yd3 (61800lb /22.4yd3 nominal payload/body) |
| HM400-3 Rated payload per cubic yard of heaped body | 2 lb | 2809 lb per yd3 (88200lb /31.4yd3 nominal payload/body) |
Komatsu HM300-3 and HM400-3: Configuration records
HM300-3
| Specification | Source figure |
|---|---|
| Dimensions and weight | |
| Overall Length | 10275 mm / 33.71 ft (European brochure) |
| Overall Width | 2900 mm / 9.51 ft (European brochure, 23.5 R25 tyres) |
| Overall Height | 3510 mm / 11.52 ft cab; 6440 mm / 21.13 ft with body raised |
| Axle Spacing — Front-to-centre and tandem axle distances are separate in the original dimension drawing. | 4100 mm / 13.45 ft front-to-centre axle; 1710 mm rear tandem spacing |
| Body and Articulation Clearances — Original manufacturer dimension arrows specify lowered body and hinge positions. | 572 mm / 1.88 ft under lowered rear body; 575 mm at articulation joint |
| Dump Height | 2830 mm / 9.28 ft loading edge; 6440 mm raised body height |
| Lowered Rear Body-Lip Clearance — Not raised-body overhead clearance or wall-to-wall turning radius. | 572 mm / 1.88 ft rear body-lip clearance in lowered drawing position |
| Dump | |
| Dump Angle | 70 degrees body raise; 45 degrees steering articulation each side |
| Earlier Lowering-Time Reference — Earlier10.5sec lowering entry retained; manufacturer lists10.5sec hoist but does not verify lowering duration. | 10.5 sec |
| Rated Payload | 28 metric tonnes / 30.9 US short tons |
| Capacity - Struck | 17.5 yd3 |
| Raise Time | 10.5 sec |
| Capacity - Heaped | 22.4 yd3 |
| Engine | |
| Number Of Cylinders | 6 |
| Engine Model | Komatsu SAA6D125E-6 |
| Gross Power | 332 hp |
| Net Power | 324 hp |
| Power Measured @ | 2,000 rpm |
| Max Torque | 1,239 lb-ft |
| Aspiration | Komatsu Variable turbo charge |
| Displacement | 11.04 L / 673.7 cu in |
| Operational | |
| Fuel Capacity | 102.6 gal |
| Hydraulic System Fluid Capacity | 27.2 gal |
| Transmission, Converter and Retarder Cooling Oil — 98L is the combined driveline/retarder oil entry; it does not establish engine coolant fill. | 98 L / 25.9 US gal is transmission/converter/retarder-cooling oil, not engine coolant |
| Engine Oil Capacity | 9.2 gal |
| Transmission Fluid Capacity | 25.9 gal |
| Tire Size | 23.5 R25 |
| Transmission and speeds | |
| Transmission Type | Auto |
| Number Of Forward Gears | 6 |
| Number Of Reverse Gears | 2 |
| Max Speed | 36.4 mph |
| Weights | |
| Total Empty | 54,917 lb |
| Total Loaded | 116,823 lb |
HM400-3
| Specification | Source figure |
|---|---|
| Dimensions and weight | |
| Overall Length | 36.44 ft |
| Overall Width | 11.32 ft |
| Overall Height | 12.26 ft |
| Axle Spacing — Front-to-centre and tandem axle distances are separate in the original dimension drawing. | 4350 mm / 14.27 ft front-to-centre axle; 1970 mm rear tandem spacing |
| Ground Clearance | 2.33 ft |
| Lowered Rear Body-Lip Clearance — Not raised-body overhead clearance or wall-to-wall turning radius. | 808 mm / 2.65 ft rear body-lip clearance in lowered drawing position |
| Dump | |
| Rated Payload | 40 metric tonnes / 44.1 US short tons |
| Capacity - Struck | 18.2 m3 / 23.8 yd3 |
| Capacity - Heaped | 24.0 m3 / 31.4 yd3 (2:1 SAE) |
| Engine | |
| Number Of Cylinders | 6 |
| Engine Model | Komatsu SAA6D140E-6 (European EU Stage IIIB configuration) |
| Net Power | 469 hp / 350 kW (ISO 9249, European brochure) |
| Power Measured @ | 2,000 rpm |
| Displacement | 15.24 L / 930.0 cu in (European brochure) |
| Operational | |
| Fuel Capacity |
|
| Tire Size | 29.5R25 |
| Transmission and speeds | |
| Transmission Type | Auto |
| Number Of Forward Gears | 6 |
| Number Of Reverse Gears | 2 |
| Max Speed | 55.9 km/h / 34.7 mph (European brochure) |
| Weights | |
| Total Empty | 33660 kg / 74207 lb (European brochure approximate weight) |
| Total Loaded | 73740 kg / 162569 lb (European brochure approximate GVW) |
More in Komatsu: HA250-3/HA270-3, HM350-2, Hm300-1–HM400-2.