Looking for 3907804 Cummins 4BT crankshaft? Factory direct supply for equipment including Case 580K and Komatsu PC120-6. Prevents journal scoring. Request a quote today!
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The Cummins 4BT 3.9L crankshaft (OEM: 3907804) is a premium forged/cast component engineered for industrial durability.
It resolves journal wear issues and fits equipment including Case 580K backhoes, Komatsu PC120-6 excavators, and Hyster forklifts.
In stock for global wholesale export.
The Cummins 4BT Crankshaft (OEM 3907804) is a forged steel replacement designed for 3.9L diesel engines in trucks, forklifts, and construction equipment across the USA market.
The Ruich Value Cummins 4BT Crankshaft is engineered for 3.9L diesel engines, ensuring OEM-level balance and reliability. It replaces multiple OEM references including 3907804 and 3931251, making it ideal for rebuilders and fleet operators in the USA.
| Specification | Value |
|---|---|
| Product Type | Crankshaft |
| Material Grade | 42CrMo Forged Steel / Premium Alloy Cast |
| Forging Type | Fully Forged & Precision Machined |
| Surface Treatment | Induction Hardened Journals |
| Main Journal Diameter | 82.96 – 82.99mm |
| Rod Journal Diameter | 68.96 – 68.99mm |
| Stroke | 120mm |
| Hardness Range | 52-58 HRC (Journals) |
| Heat Treatment | Quenched & Tempered |
| OEM Reference | 3907804 |
| Cross Reference | 3908031, 3907803, 3929339 |
| Typical Applications | Case 580K/580L, Komatsu PC120-6, Hyster Forklift, Freightliner MT35 |
| Application Category | Construction Machinery, Forklifts & Light Trucks |
We also supply a full range of Cummins crankshafts (6BT, 6CT, ISX, QSB). Please refer to our TablePress list for complete cross-references.
| Cummins Engine Model | Core Displacement (L) | Serial | Associated Models (for Cross-Reference) | Key Applications |
|---|---|---|---|---|
| B3.3 | 3.3 | B / ISB / QSB Series (Light & Mid-Range) | B3.3 (M16/18) | Skid Steer, Excavator, Forklift, Gen-Set |
| 4BT/3.9 | 3.9 | B / ISB / QSB Series (Light & Mid-Range) | 4BT3.9, 4BTA | Diesel Conversion Swap, Jeep Swap, Ford Van, Step Van |
| ISB4.5 / B4.5 | 4.5 | B / ISB / QSB Series (Light & Mid-Range) | 4ISBE, 4ISDE, ISB 4.5L Euro V | Medium-Duty Truck, Bus, Delivery Vehicle |
| 4H | 4.0 | H Series (Mid-Range) | 4H / 4HJ / 4HT | John Deere Excavators (200D/210D), Caterpillar Skid Steers (226B/232B), Komatsu Forklifts (FG20T-25), |
| 6BT / B5.9 | 5.9 | B / ISB / QSB Series (Light & Mid-Range) | 6BT5.9, 12 Valve (12V), 3965010 | Dodge Ram 1500/2500/3500 (1989-2002), Agricultural Tractor |
| ISB6.7 / QSB6.7 | 6.7 | B / ISB / QSB Series (Light & Mid-Range) | 6ISBE, 6ISDE, ISB 6.7L Euro V | Dodge Ram 2500/3500 (2007.5+), School Bus, Fire Truck |
| 6CT / ISC 8.3 | 8.3 | C / ISC / QSC Series (Mid-Range Heavy-Duty) | 6CTA, C8.3, 6D114 | Freightliner, Fire Apparatus, Motorhome (RV), Dozer |
| ISL8.9 / QSL9 | 8.9 | L / ISL / QSL Series (Heavy-Duty) | ISL, ISB 8.9L | Heavy-Duty Bus, RV Coach, Crane, Volvo/Kenworth Truck |
| M11 / ISM / QSM11 | 10.8 | M / ISM / QSM Series | - | Road Truck, Semi-Truck, Haul Truck, Gen-Set |
| NT855 | 14 | N / NT Series (Classic Mechanical) | N14, NH220 (Earlier), D85 | Peterbilt, Kenworth, Classic Truck, Heavy Equipment |
| K19 / QSK19 | 19 | K / QSK Series (High Horsepower) | KTA19, KT19 | Mining, Marine Propulsion, Drill Rig, Power Generation |
| K38 / QSK38 | 38 | K / QSK Series (High Horsepower) | KTA38, KAT38, GTA38 | Large Mining Excavator, Off-Highway, Gen-Set |
| ISF2.8 / ISF3.8 | 2.8 / 3.8 | F / ISF Series (Light Commercial) | - | Foton, GAZelle, Light Commercial Van |
| A2300 | 2.3 | A Series (Small Utility) | - | Small Gen-Set, Utility Equipment |
| ISL9 / QSL9 (6L/9.3L) | 8.9 / 9.3 | L / ISL / QSL Series | L9, ISL 9.3L Euro V/VI | Dongfeng Trucks (DFL4251), Shantui Bulldozers (SD32D), |
| NH220 | 14 | N / NT Series (Classic Mechanical) | NT855, N14, NH220 | Peterbilt 359, Kenworth W900, Classic Truck, Heavy Equipment, Vintage Tractor |
A1: Symptom: Deep scoring or “spinning” of the main bearings, leading to catastrophic engine knocking. Diagnosis: This is often caused by oil starvation or excessive particulate contamination in the lubrication system of forklifts and backhoes operating in dusty environments. Solution: Our 3907804 crankshafts undergo advanced induction hardening on all journals to increase surface density, providing superior resistance to abrasive wear compared to standard OEM replacements.
A2: Technical Detail: Main bearing bolt torque must be applied in three stages (60Nm, 90Nm, then 120Nm) and crankshaft end play must be verified within 0.10mm – 0.43mm. Pro-Tip: Always clean the internal oil galleries of the new shaft with a brush and solvent before installation to remove any residual anti-rust coating that could block oil flow to the rod bearings.
A3: Diagnosis: 4BT engines used in 4-cylinder high-torque applications like the Komatsu PC120-6 suffer from stress concentration at the journal fillets. Our Solution: We implement radius-fillet hardening and precision grinding. This ensures that the 3907804 shaft can withstand the higher vibration frequencies typical of 4-cylinder diesel engines, preventing the initiation of fatigue cracks that lead to shaft fracture.
Contact us via Contact Form for bulk pricing on this Cummins 4BT Crankshaft. We support distributors, repair facilities, and fleet managers worldwide.
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