Gehl SL5635 and SL6635 Series II Skid Loaders Service Repair Manual
Gehl Sl5635 & Sl6635 Series Skid Loaders Operators Manual
The service repair manual is structured for professional mechanics, ensuring full control over every system component.
Complete Service Repair Manual Coverage
Manual Sections
- General information and safety protocols
- Engine service and overhaul procedures
- Hydraulic system diagnostics and repair
- Hydrostatic drive system servicing
- Electrical system schematics and troubleshooting
- Loader frame, lift arms, and attachment systems
- Preventive maintenance schedules and lubrication
Engine System – Detailed Service Procedures
The diesel engines in both models are designed for consistent torque output and fuel efficiency.
Engine Maintenance and Repair
- Full engine teardown and rebuild procedures
- Cylinder head inspection and valve adjustments
- Fuel injection pump calibration
- Turbocharger inspection (if equipped)
- Cooling system pressure testing and flushing
Gehl SL5635 and SL6635 Series II Skid Loaders Service Repair Manual – Engine Troubleshooting
| Symptom | Cause | Solution |
|---|---|---|
| Hard starting | Weak battery or injectors | Test battery and clean injectors |
| Overheating | Low coolant or clogged radiator | Flush system and refill |
| Power loss | Fuel restriction | Replace filters |
Hydraulic System – Performance Diagnostics and Repair
The hydraulic system is central to loader arm movement and attachment operation.
Hydraulic Components
- Tandem gear pumps
- Control valve assemblies
- Lift and tilt cylinders
- Hydraulic hoses and fittings
- Oil reservoir and filtration system
Diagnostic Procedures
- System pressure testing with gauges
- Flow rate analysis under load
- Seal and hose inspection for leaks
- Valve spool wear evaluation
Common Hydraulic Issues
| Issue | Root Cause | Action |
|---|---|---|
| Weak lifting force | Pump wear | Replace pump |
| Jerky movements | Air contamination | Bleed system |
| Slow response | Dirty filters | Replace filters |
Hydrostatic Drive System – Service and Calibration
The hydrostatic transmission provides smooth speed control and directional changes.
Service Coverage
- Hydrostatic pump and motor inspection
- Drive chain tension adjustment
- Final drive lubrication
- Control linkage calibration
Diagnostic Insights
- Loss of traction → Inspect hydrostatic pump
- Uneven movement → Check motor output balance
- Noise during travel → Inspect bearings and chains
Electrical System – Advanced Troubleshooting
A reliable electrical system ensures proper machine startup and monitoring.
Electrical Components
- Battery and charging system
- Starter motor and alternator
- Wiring harness and connectors
- Control switches and sensors
Testing Workflow
- Verify battery voltage (12V standard)
- Inspect fuse panel for continuity
- Test alternator output (13.5–14.5V)
- Check grounding points
Loader Frame, Lift Arms, and Attachments
Structural components must be maintained to ensure operational safety and load stability.
Inspection Points
- Lift arm pivot pins and bushings
- Quick attach mechanism
- Frame weld integrity
- Bucket linkage wear
Maintenance Actions
- Grease all pivot points regularly
- Replace worn bushings
- Inspect welds for cracks
- Ensure proper attachment locking
Preventive Maintenance Schedule
A structured maintenance schedule reduces downtime and extends machine lifespan.
Service Intervals
| Interval | Task |
|---|---|
| Daily | Inspect fluids, leaks, and safety components |
| 50 Hours | Lubricate all grease fittings |
| 250 Hours | Change engine oil and filters |
| 500 Hours | Replace hydraulic filters |
| 1000 Hours | Inspect hydrostatic system |
Fluid Specifications and Lubrication Requirements
Using correct fluids is essential for system performance and longevity.
Recommended Fluids
- Engine Oil: SAE 15W-40 diesel
- Hydraulic Oil: ISO VG 46
- Coolant: 50/50 antifreeze mix
- Chain Case Oil: Manufacturer-approved lubricant
The following checklist is an important reminder of valuable information 5635sx and inspections which MUST be made before delivering the loader to the customer. Check off each item after the prescribed action is taken.
Service Repair Manual Covers
Specifications
Safety
Lubrication
Mainframe
Wheel Drives
Controls
Hydrostatic System
Hydraulic System
Electrical System
Engine sl6635
