![Hyundai HL770A Repair Manual [Wheel Loader]](https://youfixthis.com/wp-content/uploads/2016/02/2016-02-16_11-07-01-1-300x300.jpg)
Part of the Hyundai Repair Manuals.
Wrenching on a Hyundai HL770-9 or HL770XTD-9? This 640-page service manual PDF covers both wheel loader variants, from the torque converter to the bucket pins. Inside: complete wiring diagrams with connector pinouts, hydraulic schematics for the full circuit, transmission fault codes for the electro-hydraulic shift control, and step-by-step disassembly procedures for the transmission, axles, brakes, steering, and work equipment. A full troubleshooting section covers resistance measurements and operational checks. Torque the main pump housing mounting bolts to 19.6±2.9 kgf·m, and replace brake linings once residual thickness drops below 2.0 mm. Chasing an electrical gremlin through your loader's harness is no way to spend a Friday. Bookmarked by system and keyword-searchable; download it, find the spec, and get your machine back on the pile.
What's Inside This Hyundai HL770-9, HL770XTD-9 Manual
| System | Pages | Key Topics |
|---|---|---|
| General | 1-36 | Safety Hints, Specifications, Operational Checkout Record Sheet |
| Engine | 37-45 | Engine Speed and Stall RPM, Fuel Warmer System |
| Power Train System Overview | 46-50 | Component Overview, Hydraulic Circuit, Torque Converter, Hydrodynamic Torque Converter |
| Transmission Structure and Operation | 51-66 | Transmission Layout, Installation View, Forward/Reverse Gear Operation, Electro-Hydraulic Shift Control, Gear Selector, Electric Control Unit |
| Transmission Fault Codes | 67-77 | Machine Fault Codes, Engine Fault Codes, Operating Modes |
| Transmission Troubleshooting and Testing | 78-113 | Transmission Fault Detection, Resistance Measurement, Axle Operation, Differential Operation, Tire and Wheel, Operational Checks |
| Transmission Disassembly and Assembly | 114-320 | Control Valve Disassembly, Transmission Disassembly, Multi-Disc Clutch Dismantling, Bearing Preload Adjustment, Axle Disassembly, Differential Carrier Disassembly |
| Brake System | 321-367 | Operational Checks and Troubleshooting, Tests and Adjustments, Disassembly and Assembly |
| Steering System | 368 | Operational Checks and Troubleshooting, Tests and Adjustments, Disassembly and Assembly |
| Structure and Function | 369-462 | Flow Amplifier, Steering Unit, Steering Cylinder |
| Work Equipment | 463-554 | Operational Checks and Troubleshooting, Tests and Adjustments, Disassembly and Assembly |
| Electrical System | 555-640 | Component Location, Electrical Circuit, Monitoring System, Electrical Component Specification, Connectors, Troubleshooting |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Engine mounting bolt, nut (rubber, 2EA) | 100±15 kgf·m | p. 31 |
| Main pump housing mounting bolt | 19.6±2.9 kgf·m | p. 30 |
| Steering cylinder Bore dia × Rod dia × Stroke | Ø 95 × Ø 50 × 480 mm | p. 30 |
| Emergency release actuation torque | 40 Nm to 70 Nm | p. 345 |
| Min. residual thickness of brake lining | 2.0 mm | p. 346 |
| Gland tightening torque | 50±5 kgf·m (362±36 lbf·ft) | p. 451 |
| Hydraulic oil tank capacity | 200 L | p. 517 |
| Hydraulic oil filter replacement interval | 250 operating hours | p. 530 |
| Pilot cut off, parking brake, attach lock, unlock solenoid resistance | 15~25 Ohm | p. 607 |
| Engine Oil Quantity | 23L | p. 27 |
| HL770-9 | ||
| Operating Weight | 23100 kg | p. 22 |
| HL770XTD-9 | ||
| Operating Weight | 23850 kg | p. 23 |
Hyundai HL770-9, HL770XTD-9 Common Problems This Manual Covers
Hyundai HL770-9 bucket lifts slowly and boom drifts down under load after oil warms up
Check hydraulic oil level in the 200 L tank and inspect the return filter; replace it if past the 250 hour service interval. Test main relief pressure against the 280 kgf/cm2 spec on page 28. If pressure stays low with a clean filter, suspect main pump wear or internal cylinder leakage.
Manual Section: Work Equipment p. 463Machine will not move in any gear or drops out of gear intermittently under load
Check for stored transmission fault codes on page 65 before pulling anything apart. Run the low pressure and stall checks in the troubleshooting procedures starting on page 108. Verify transmission oil level with the engine warm at low idle, 800 ± 50 rpm; low oil mimics clutch slippage and no-move complaints.
Manual Section: Transmission Troubleshooting p. 108Brake pedal feels weak and machine pulls to one side when stopping loaded
Test service brake pressure at the test port; the spec is 80 ± 5 bar on page 367. Measure brake lining residual thickness and replace any disc worn to 2.0 mm. Set brake clearance between 1.0 mm and 3.0 mm, then bleed each wheel end until fluid runs clear with no air.
Manual Section: Brake System p. 321Steering turns hard at idle and assist fades during tight loading cycles
Check hydraulic oil level first; hard steering at idle usually points to pump flow, so raise engine speed toward high idle, 2030 ± 50 rpm, and retest. Inspect steering cylinder rods for scoring and reseal any leaking cylinder, torquing the gland to 50 ± 5 kgf·m per page 451. Test the flow amplifier if assist stays weak.
Manual Section: Steering System p. 368Parking brake will not release and cluster warning lamps stay on after startup
Measure parking brake solenoid resistance at the connector; normal range is 15 to 25 Ohm per page 607. Check supply voltage and grounds using the wiring diagram before swapping parts. If resistance and voltage both check good, look for a failed relay or a chafed harness near the articulation joint.
Manual Section: Electrical System p. 555Frequently Asked Questions
What is the torque specification for the engine mounting bolt (bracket, 8EA) on the Hyundai HL770-9?
The torque specification for the engine mounting bolt (bracket, 8EA) is 10.7 ± 1.6 kgf·m (77.4 ± 11.6 lbf·ft). p. 30
What is the recommended engine oil capacity for the Cummins QSL engine in the HL770-9?
The engine oil quantity for the Cummins QSL engine is 23 liters (6.1 U.S. gallons). p. 27
What is the replacement interval for the engine oil filter on the HL770-9?
The engine oil filter should be replaced every 500 operating hours. p. 594
What is the procedure for bleeding the hydraulic brake system on the HL770-9?
To bleed the brake system, push and hold the brake pedal down until the bleeding procedure is complete. If bubbles continue for more than 2 minutes, stop the procedure and check for problems. Detailed steps are provided on page 358. p. 358
What is the tightening torque for the transmission output flange hexagon screws on the HL770-9?
The tightening torque for the transmission output flange hexagon screws is 4.69 kgf·m (33.9 lbf·ft). p. 202
How is this Hyundai HL770-9 Service Manual delivered?
A single searchable PDF file of 640 pages, downloadable right after payment. Nothing ships, nothing waits in the mail.
Does this Hyundai HL770-9 manual allow printing?
You can. The PDF is unlocked and carries no copy protection, so print the sections you want and keep the file as your backup.
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