This Gehl service manual covers the SL3640, SL3840, and SL4240 skid-steer loaders, powered by the Yanmar 3TNV88-XMS2 and 4TNV88-XMS2 diesel engines. Its 164 pages guide assembly and disassembly, adjustment, testing, troubleshooting, and replacement across the whole machine.Sections cover specifications and lubrication, the mainframe and ROPS, wheel drives and drive chains, controls, the hydrostatic and hydraulic systems, the electrical system, and the engine. You get charge pressure tests, relief valve settings, cylinder tests, self-leveling valve adjustment, and torque values throughout.Owners and independent mechanics can use it to fix slow or weak hydraulics, adjust drive chains, test the lift and tilt circuits, and diagnose electrical faults. Main hydraulic system pressure is 2750 psi (190 bar) and wheel nut torque is 120 ft-lbs (163 Nm). It downloads instantly as a searchable, printable PDF.
What's Inside This Gehl SL3640, SL3840, SL4240 Manual
| System | Pages | Key Topics |
|---|---|---|
| Introduction | 2-6 | General Information, Table Of Contents, Tire Options, Buckets and Capacities, Safety, Signal Words, Additional Safety Reminders, Mandatory Safety Shutdown Procedure |
| Specifications | 7-8 | Tire Options, Buckets and Capacities, General Specifications |
| Safety | 9-16 | - |
| Lubrication | 17-20 | Hydraulic Oil Reservoir, Crankcase Oil, Hydraulic Oil Tank Drain Procedure, Chaincases, Chaincase Oil Change Procedure, Grease Fitting Locations, Cooling System Drain Procedure |
| Mainframe | 21-40 | Introduction, Engine Access Cover Removal and Installation, Rollover Protective Structure Removal and Installation, Seat Removal and Installation, Seat Slide Replacement |
| Wheel Drives | 41-46 | Introduction, Drive Chain Adjustment, Drive Chain Removal and Installation, Axle Removal and Installation |
| Controls | 47-68 | Introduction, Control Handle Removal and Installation, Control Handle Position and Tracking Adjustment, Dual Control Weldment Removal and Installation - T-Bar Controls |
| Hydrostatic System | 69-80 | Introduction, Troubleshooting Guide, Charge Pressure Test and Adjustment, Hydrostatic Pump Relief Valves, Drive Motor Hot Oil Shuttle Valve |
| Hydraulic System | 81-112 | Introduction, Troubleshooting Guide, System Pressure Test - Control Valve, Tilt Cylinder Test, Self-Leveling Valve Test, Self-Leveling Valve Adjustment, Lift Cylinder Test |
| Electrical System | 113-132 | Description of Operation, Troubleshooting Guide, Relay Test and Operation, Electrical Circuits, Seat Switch Removal and Installation, Restraint Bar Switch Removal and Installation |
| Engine | 133-154 | Introduction, Troubleshooting Guide, Engine Oil Filter Element Removal and Installation, Air Cleaner Assembly Removal and Installation, Air Filter Element Removal and Installation |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Wheel nut torque | 120 ft.-lbs. (163 N•m) | p. 43 |
| Axle hub slotted locknut torque (initial) | 100 ft.-lbs. (136 N•m) | p. 45 |
| Solenoid valve coil retaining nut maximum torque | 45 in.-lbs. (5,1 N•m) | p. 109 |
| Hydrostatic pump arm capscrew torque | 30 ft.-lbs. (40 N•m) | p. 72 |
| Auxiliary hydraulics screw/cap and washer/lock torque | 30 ft./lbs. | p. 97 |
| Hydraulic oil filter element replacement interval (initial) | 50 hours | p. 18 |
| Hydraulic oil filter element replacement interval (regular) | 500 hours | p. 18 |
| Hydraulic oil viscosity (too high/heavy) | Allow longer warm-up or replace oil with the proper viscosity oil. | p. 71 |
| Low engine speed | Operate engine at higher speed. | p. 84 |
| Hydrostatic drive overheating causes | Drive system overloaded continuously; Lift, tilt or auxiliary system overloaded continuously; Drive motor(s) or hydrostatic pump(s) have internal damage or leakage; Oil cooler fins are plugged with debris; Loader being operated in a high temperature area with no air circulation. | p. 72 |
| Hydrostatic (drive) system noisy causes | Hydraulic oil viscosity is too high; Air in hydraulic system. | p. 71 |
| Engine Oil Capacity | 7.6 US qts. (7,2 L) | p. 7 |
Gehl SL3640, SL3840, SL4240 Common Problems This Manual Covers
Lift arms will not raise or hold
Lift arms that will not raise or drop under load often trace to a lift solenoid valve malfunction, poor electrical connections, or a leaking lift spool. The Hydraulic System section covers the control valve system pressure test, the self-leveling valve, and the lift cylinder test to isolate it.
Manual Section: Hydraulic System p. 81Hydraulics slow or weak until warm
Functions that are sluggish cold and improve after warm-up usually point to oil that is too heavy or a low engine speed. The Hydrostatic System section covers the charge pressure test and adjustment and the pump relief valves used to confirm the cause.
Manual Section: Hydrostatic System p. 69Oil level drops or system runs hot
A hydraulic level that keeps falling, or a system that runs noisy and hot, usually means external hose or fitting leaks or air ingress. The Hydraulic System section covers the hoses, tubing, and troubleshooting guide for locating and correcting leaks.
Manual Section: Hydraulic System p. 81Drive chain wear or slack
Loose or worn drive chains cause uneven tracking and drivetrain noise. The Wheel Drives section covers drive chain adjustment, removal and installation, and axle service to restore correct tension.
Manual Section: Wheel Drives p. 41Machine will not crank or start
A no-crank or intermittent start can be a battery, relay, safety switch, or wiring fault. The Electrical System section describes circuit operation, relay test and operation, and the seat and restraint bar switches used to trace the problem.
Manual Section: Electrical System p. 113Engine power loss from intake restriction
Degraded engine performance can follow loose or cracked intake tubes, elbows, and clamps or a dirty air filter. The Engine section covers the air cleaner assembly and air filter element service that keep intake airflow clean.
Manual Section: Engine p. 133Frequently Asked Questions
Which models and engines does this manual cover?
It covers the Gehl SL3640, SL3840, and SL4240 skid-steer loaders, powered by the Yanmar 3TNV88-XMS2 and 4TNV88-XMS2 diesel engines.
Is this the complete service manual?
Yes. Its 164 pages cover specifications, lubrication, the mainframe, wheel drives, controls, the hydrostatic and hydraulic systems, the electrical system, and the engine, with disassembly, testing, and replacement procedures.
What is the hydraulic system pressure and how do I test it?
Main hydraulic system pressure is 2750 psi (190 bar). The Hydraulic System section covers the system pressure test at the control valve, along with tilt cylinder, self-leveling valve, and lift cylinder tests. p. 81
What is the wheel nut torque?
Wheel nut torque is 120 ft-lbs (163 N-m). The Wheel Drives section also covers axle service and drive chain adjustment procedures. p. 41
Is this Gehl SL3640, SL3840, SL4240 Service Manual a digital download?
A 164-page Service Manual in searchable PDF, ready the moment checkout completes. Open it on a computer, tablet, or phone with no shipping wait.
Can I print specific sections of this Gehl SL3640, SL3840, SL4240 manual?
Yes. The PDF carries no DRM, so you can print any page or section you need for the shop on any standard printer.
Does this Gehl SL3640, SL3840, SL4240 manual include wiring diagrams?
Included. The Gehl SL3640, SL3840, SL4240 Service Manual covers complete wiring harness diagrams, electrical circuits, and connector pinouts.
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