Part of the John Deere Repair Manuals.
This is the complete John Deere factory diagnostic and repair manual (TM2138) for the 3120, 3320, 3520 and 3720 compact utility tractors. Across 1,849 pages it walks a technician through every major system: diagnosing the Yanmar diesel engine, tracing North American and European wiring schematics (including MY08 and MY13 harness layouts), repairing the mechanical power train and eHydro hydrostatic transmission, servicing the final drive and PTO, testing and repairing the hydraulic system, and overhauling the steering and brakes. This is the same material a John Deere dealer technician uses, with engine torque values, hydraulic test pressures, wear limits, and wiring diagrams called out so every repair is done to spec.
What's Inside This John Deere 3120, 3320, 3520, 3720 Manual
| System | Pages | Key Topics |
|---|---|---|
| Specifications and Information | Metric and Inch Bolt Torque Values, O-Ring Fitting Service, Gasket Sealant, Fuel and Lubricant Specifications, Engine Oil Viscosity Grades, Coolant Requirements, Serial Number Locations | |
| Engine | Yanmar 3TNV84/3TNV88/3TNV84T/3TNV84HT Specs, Component Location, Fuel System Operation, Cooling System, Lubrication, Turbocharger, Engine Diagnostics, Compression Test, Valve Adjustment, Fuel Injection Pump Timing, Engine Repair and Rebuild | |
| Electrical System (Na) | North American Schematics and Harnesses, MY08 Harness Layouts, MY13 Harness Layouts, Common Schematics, Operation and Diagnostics, Tests and Adjustments, Display Panel Tests, Servicegard Tests, Service Advisor, Electrical Repair | |
| Electrical System (Eec) | European Schematics and Harnesses, MY08 Harness Layouts, MY13 Harness Layouts, Common Schematics, Eec Troubleshooting, Operation and Diagnostics | |
| Power Train (Mechanical) | Prt Specifications, Component Location, Theory of Operation, Diagnostics, Troubleshooting, Tests and Adjustments, Mechanical Power Train Repair | |
| Power Train (Hydrostatic) | eHydro Specifications, Hydrostatic Schematics, Theory of Operation, Hydrostatic Diagnostics, Troubleshooting, Tests and Adjustments, Hydrostatic Transmission Repair | |
| Power Train (Final Drive and PTO) | Final Drive Specifications, Component Location, Theory of Operation, Final Drive Diagnostics, Troubleshooting, Tests and Adjustments, Final Drive Repair, PTO Theory of Operation, PTO Repair | |
| Hydraulic System | Hydraulic Specifications, Component Location, Hydraulic Schematics, Theory of Operation, Hydraulic Diagnostics, Tests and Adjustments, Hydraulic System Repair | |
| Steering | Steering Specifications, Component Location, Theory of Operation, Steering Diagnostics, Tests and Adjustments, Steering Repair | |
| Brakes | Brake Specifications, Component Location, Theory of Operation, Brake Diagnostics, Tests and Adjustments, Brake Repair | |
| Miscellaneous | Additional Specifications, Miscellaneous Repair Procedures |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 3120 | ||
| Engine - Model 3120 | Yanmar 3TNV84, 3-cylinder, 4-cycle diesel, 1.496L (91.3 cu in), bore 84 mm, stroke 90 mm | |
| 3320 | ||
| Engine - Model 3320 | Yanmar 3TNV88, 3-cylinder, 4-cycle diesel, 1.642L (100.2 cu in), bore 88 mm, stroke 90 mm | |
| 3520 | ||
| Engine - Model 3520 | Yanmar 3TNV84T (turbocharged), 3-cylinder, 4-cycle diesel, 1.496L (91.3 cu in) | |
| 3720 | ||
| Engine - Model 3720 | Yanmar 3TNV84HT (high-output turbo), 3-cylinder, 4-cycle diesel, 1.496L (91.3 cu in) | |
| All models | ||
| Engine Torque at Rated Speed (2600 rpm) | 3120: 75.4 N.m (55.6 lb-ft) / 3320: 83.5 N.m (61.6 lb-ft) / 3520: 96.4 N.m (71.1 lb-ft) / 3720: 114.3 N.m (84.3 lb-ft) | |
| Rated Engine Speed | 2600 +/- 10 rpm | |
| Slow Idle Speed | 1000 +/- 50 rpm | |
| Cooling System Capacity | 5.3L (5.6 qt) approximate | |
| Engine Oil Capacity (with Filter) | 4.3L (4.5 qt) approximate | |
