All 158 pages of this Eagle Tugs USATS parts and service manual PDF (OEM #REV17 1.7.16) focus on one thing: keeping your tow tractor and its Yanmar 4TNV98 Tier II and Tier III engines running strong on the tarmac. Inside, you get complete electrical wiring diagrams, full hydraulic schematics, and detailed drivetrain parts breakdowns. Open to the maintenance section for preventative schedules, front end alignment procedures, and page after page of Yanmar diesel torque charts. Lock down the rear Dana 60 axle drive pinion nut to 240-300 lbs-ft, and ensure your emergency tire air pressure is set to exactly 25 PSI before putting the tug back in service. Ground support equipment downtime costs airlines money. Download this bookmarked file right to your tablet, find the exact spec you need, and get the tractor back to work.
What's Inside This Eagle Tugs USATS Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 3-6 | Purpose & Use of This Manual, Technical Assistance, Ordering Spare/Service Parts, Contact Information |
| Warranty & Safety | 7-12 | Important Safety Notice, Warranty Information, Vehicle ID Information, Warranty Registration, Yanmar Engine Warranty Information, Service Bulletin Esb-02-08 Fuel Requirements |
| Identification Key | 13 | - |
| Crankshaft & Piston Assembly Tier Ii | 14-27 | Alternator Assembly, Power Train, Fan Bracket Spacer Information, Cylinder Block Assembly Tier Ii, Head Cover Assembly, Cylinder Block Assembly Tier Iii |
| Engine Gaskets Tier Iii | 28-43 | Oil Pan Assembly, Camshaft & Driving Gear Assembly Tier Ii, Crankshaft & Piston Assembly Tier Iii, Camshaft & Driving Gear Assembly Tier Iii, Governor Assembly Tier Iii Only, Engine Gear Housing Assembly, Engine Oil Lube System, Engine Gaskets Tier Ii |
| Axle Assembly Breakdown, Front Drive (Awd) | 44-61 | Drive Shaft Assembly-Rear, Cooling System Radiator Assembly Manufactured Before Feb 1, 2012, Cooling System, Cooling System Radiator Assembly Manufactured After Feb 1, Driveline, Transaxle Case Extension & Retainer, Transmission |
| Hydraulic Assist with Prince Pump | 62-78 | Drum Brake Assembly Rear, Axle Assembly Breakdown, Rear Drive, Brakes, Brake System Hydraulic, Brake Actuator Assembly, Hydraulic System |
| Engine Fuel Line Tier Iii | 79-93 | Fuel Tank Assembly, Steering System, Hydraulic Assist Schematic, Air Cleaner, Fuel System, Engine Fuel Line Tier Ii, Fuel Injection Lines & Nozzle Tier Ii, Fuel Injection Pump Tier Ii |
| Quick Start Guide with Sauer Display | 94-107 | Intake Manifold Tier Iii, Intake Manifold Tier Ii, Exhaust & Intake System, Exhaust Manifold Tier Iii, Operator Compartment, Exhaust System - Units Built After 9/2013, Exhaust System - Units Built Prior to 9/2013, Accelerator Pedal Assembly Tier Ii |
| Wiring Harness Yanmar-Vehicle to Engine Tier Iii Manufactured Before Oct 2013 | 108-123 | Wiring Harness, Dash, Lights & Electrical, Instrument Panel with Analog Gauges, Instrument Panel with H30 Display, Headlight & Taillight Assembly, Wiring Harness Yanmar-Vehicle to Engine Tier Ii Manufactured Before Feb 1, 2012, Vehicle Connector Harness, Yanmar Tier Ii Diesel Manufactured Feb 1, 2012 to Present, Vehicle Logic Harness, Yanmar Tier Ii Diesel Manufactured Before Feb 1 |
| Hip Restraint | 124-139 | Wiring Harness Yanmar Engine Tier Iii, Wiring Harness Yanmar Engine Tier Ii Manufactured Before Feb 1, 2012, Wiring Harness Yanmar-Vehicle to Engine Tier Iii Manufactured Oct 2013 to Present, Wiring Harness Yanmar Engine Tier Ii Manufactured Feb 1, 2012 to Present, Side Access Door, Other Assemblies |
| Maintenance | 140-157 | Daily Operator Responsibilities, Lubrication Chart, Preventative Maintenance Schedule, Front End Alignment Procedure, Tips for All Weather Traction During Aircraft Pushback |
| Revision Log | 158 | - |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Standard Torque Chart - M6 x 1.0 | 87-105 in-lb | p. 14 |
| Standard Torque Chart - M16 x 1.5 | 160-174 ft-lb | p. 14 |
| Emergency Tire Air Pressure | 25 PSI | p. 145 |
| Lug Nut Torque | 150 FT LBS | p. 132 |
| Hydraulic Hose (3/8" High Press 350 WK PSI) | 12" | p. 75 |
| Engine Coolant Type | ETHYLENE GLYCOL/ WATER (50/50 MIX) MIL-A-46153 | p. 141 |
| Transmission Oil Type | DEXTRON III TYPE TRANSMISSION FLUID | p. 141 |
| Transmission Refill Capacity (3.3 L Diesel) | 3.80 LITRES | p. 151 |
| Fuel Tank Refill Capacity | 24.0 U.S. GALLONS | p. 150 |
| Brake Fluid Type | DOT 5 BRAKE FLUID | p. 151 |
| Front End Toe Out | + 1/16 inch | p. 144 |
| Engine Oil and Filter Service Interval | every 250 hours | p. 142 |
Eagle Tugs USATS Common Problems This Manual Covers
Eagle Tugs Usats transmission slips under heavy load or tractor loses all forward drive p. 151
Inspect the drivetrain components shown. Check the transmission fluid level and look for external leaks. Drain the old fluid completely and refill the system with exactly 8.00 U.S. PINTS of Dextron III type transmission fluid as specified on page 151 before testing the unit under load.
Manual Section: MaintenanceEngine temperature warning light turns on and coolant boils over during aircraft pushback operations p. 141
Inspect the radiator for blocked airflow and check the coolant level on page 140. Top off the system using an Ethylene Glycol/Water (50/50 mix) MIL-A-46153 coolant as detailed on page 141. Replace the engine oil and filter every 250 hours to prevent severe internal heat buildup.
Manual Section: MaintenanceExcessive play in the steering wheel and severe inner tire wear on the front axle p. 144
Inspect the front axle linkage and verify the emergency tire air pressure is at 25 PSI per page 145. Adjust the tie rods following the front end alignment procedure on page 144 to achieve a front end toe out of exactly + 1/16 inch. Torque all hardware to spec.
Manual Section: Front End Alignment ProcedureHeavy clunking noise from the front axle and loose wheel stud nuts after towing p. 155
Inspect the chassis parts diagram on page 132 and verify all wheel stud nuts are tightened to 150 FT LBS. Check the front axle components. Torque the Dana 44 front drive pinion nut to 175-225 LBS.-FT as instructed on page 155 to eliminate driveline slack.
Manual Section: MaintenanceDiesel engine turns over but will not start or suddenly shuts down during normal operation p. 146
Drain water from the fuel filters and verify the tank contains clean diesel. Review the troubleshooting procedures on page 146 to diagnose running issues. If the system ran dry, prime the fuel lines and fill the tank to its 24.0 U.S. GALLONS refill capacity according to page 150.
Manual Section: Yanmar Engine Trouble Shooting GuideFrequently Asked Questions
What do Eagle Tugs error codes mean?
The manual provides a comprehensive list of Yanmar Engine Error Codes, including their Diagnostic Trouble Code (DTC), description, Suspect Parameter Number (SPN), and Failure Mode Identifier (FMI). For instance, DTC P0117 indicates "Engine Coolant Temperature Sensor: Shorted to low source" with SPN 110 and FMI 3.
Where can I find Eagle USATS torque specs?
Torque specifications for Eagle USATS tugs can be found in two main sections. The "STANDARD TORQUE CHART" on page 14 provides general tightening torque values for engine dress bolts, such as M6 x 1.0 bolts requiring 87-105 in-lb. Additionally, specific torque specifications for Dana 44 and Dana 60 axles are detailed on page 155, including values like 175-225 lbs-ft for the Drive Pinion Nut on a Dana 44 axle.
How do I troubleshoot an Eagle tug that will not start?
To troubleshoot an Eagle tug that will not start, consult the "Yanmar Engine Trouble Shooting Guide" on page 147. Probable causes include "No diesel fuel," which requires you to "Refuel and prime fuel system," or "Air in fuel system," which also requires priming the fuel system. If the starter motor operates but the engine does not start, check for improper diesel fuel or a clogged fuel filter.
What are the replacement specifications for drive belts?
The manual lists part numbers for replacement drive belts. For instance, the alternator belt for Tier III engine models with high output alternator is part number 9440, as seen on page 15 and 19. A V-belt is also listed with part number 25132-004200 on page 45.
What format is this manual in?
A 158-page Parts and Service Manual in searchable PDF format, available the moment you complete checkout. View on computer, tablet, or phone, with no shipping wait.
Am I able to print pages from this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Can I find hydraulic circuit diagrams in this Eagle Tugs Usats manual?
Yes. The manual includes hydraulic circuit diagrams, system schematics, and component specifications with pressure ratings.
Document Quality
This document is a scanned PDF with an accurate OCR layer, allowing you to search and copy the full text content. The text is crisp and consistently easy to read throughout all pages. Diagrams and illustrations are clear raster images, and their labels are readable. The pages are clean, free from scan artifacts, stains, or skewed content. Please note that pages 2, 8, 18, 78, and 154 are intentionally left blank.
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