Steering, transmission and axle faults each get their own troubleshooting section in this Daewoo Mega 300-III shop manual PDF, a 277-page factory document (OEM ID 2023-7105E) for the Mega 300-III wheel loader. Its hydraulic schematic traces the pump, the pilot valve and the circuits behind automatic bucket return-to-dig, boom kick-out and boom float, while the electrical schematics map the 24 volt start, preheat and wiper circuits against a wiring color code. Drivetrain coverage runs deep. Teardown and assembly procedures reach the WG-180 control valve, K3/K4 clutch pack shim selection and both torque converter types. Confirm the thermostat starts opening at 82°C (180°F), and hold the steering pump circuit to its 175 kg/cm² (2489 psi) maximum. For your transmission filter change, the oil filter tightens to 1.6 to 2.1 kg m (11.5 to 15 ft lb). Bookmarks split the file by system, and a text search for 'priority valve' takes you straight to that page.
What's Inside This Daewoo MEGA 300-III Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety | 5-17 | To the Operator of a Daewoo Wheel Loader, Basic Wheel Loader Operating Safety, Locations of Safety Labels, Summary of Safety Precautions for Lifting, Operation, Equipment |
| Specifications | 18-26 | Component Locations, Excavator Engine Specifications, Engine Performance Curves, Working Range and Dimensions, Working Capacities, Approximate Weight of Workload Materials |
| Inspection, Maintenance and Adjustment | 27-54 | Preventive Maintenance, Safety Precautions, Maintenance Intervals, Table of Recommended Lubricants |
| Drive Train and Transmission Overview | 55-60 | Drive Train Layout, Transmission External Assemblies, Mechanical Layout, Hydraulic Schematic, Transmission Troubleshooting |
| Control Valve Disassembly and Assembly | 61-74 | Control Valve Exploded View, Disassembly Steps, Assembly Steps, Wg-180 Control Valve, Second Gear Valve |
| Transmission Disassembly and Final Drive | 75-102 | Transmission Disassembly, Final Drive Disassembly, Output Shaft Assembly, End Plate Selection, Speedometer Drive Assembly |
| Clutch Pack and Power Take-Off Shaft Assembly | 103-121 | K3/K4 Clutch Pack Assembly, Shim Selection, Power Take-Off Shaft Assembly, Emergency Steering Pump, RPM Transmitter |
| Torque Converter Assembly | 122-166 | Converter Control Valve, Pump Installation, Type a Torque Converter Assembly, Type B Torque Converter Assembly, WK Converter Clutch Valve |
| Power Steering | 167-188 | Power Steering System (Steering System Troubleshooting, Steering Unit, Priority Valve) |
| Axles | 189-206 | Front and Rear Axles (Axle Troubleshooting, Front Axle Housing, Axle Differential, Planetary Gear Set, Parking Brake, Rear Axle, Brake System) |
| Hydraulic System | 207-251 | Hydraulic Circuits Description (Hydraulic Pump, Hydraulic Circuits and Components, Manually Controlled Pilot Valve) |
| Engine | 252-262 | Engine Specifications (Valve Adjustment Sequence, Engine Cylinder Compression Test, Wear Limits of Major Engine Components, Engine Oil Pump Overhaul and Rebuilding, Fuel Injection Pump Installation, Alignment and Timing, Cylinder Head Bolt Torque Requirements) |
| Electrical System | 263-273 | Electrical Schematic (Volt Operation, Wiring Color Code for Electrical Schematic Diagrams, Engine Start Circuit, Engine Stop Motor, Engine Intake Preheat Circuit, Windshield Wiper Circuit, Electrical System Schematic) |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cutting Edge fitting torque (1/4 RG, 1/4 BSP.F, R 1/4, G 1/4) | 4 kg m (29 ft lb) | p. 184 |
| Cutting Edge fitting torque (1/2 RG, 1/2 BSP.F, R 1/2, G 1/2) | 10 kg m (72 ft lb) | p. 184 |
| Filter element bypass | 1.8 kg/cm2 – 2.3 kg/cm2 (25.6 psi – 32.7 psi) | p. 256 |
| Thermostat Temperatures | Opening begins @ 82°C (180°F), Fully open @ 95°C (203°F) | p. 20 |
| Maximum pressure (steering pump circuit) | 175+30 -10 kg/cm² (2489+427 -142 psi) | p. 232 |
| Unloading pressure (steering pump circuit) | 160±5 kg/cm² (2275±71 psi) | p. 232 |
| M10 Bolt Torque | 4.8 kg m (35 ft lb) | p. 177 |
| Transmission Oil Filter Torque | 1.6 to 2.1 kg m (11.5 to 15 ft lb) | p. 36 |
| 3/8 – 16 NC Bolt Torque | 4.8 kg m (35 ft lb) | p. 177 |
| Filter cartridge bypass | 4.0 kg/cm2 – 4.8 kg/cm2 (56.9 psi – 68.3 psi) | p. 256 |
| Radiator leak test | 1.0332 kg/cm2 (14.7 psi) | p. 256 |
| Pressure valve | 0.5 kg/cm2 (7 psi) | p. 256 |
Daewoo MEGA 300-III Common Problems This Manual Covers
Daewoo Mega 300-III wheel loader torque converter and transmission fluid temperature running too high
Check transmission fluid level and fill if low. Compare oil cooler temperature with transmission temperature per page 59: if they match, clean the dirt-packed cooler; a healthy cooler runs 8 to 10°C lower. Measure converter outlet pressure against 3.0 to 6.5 bar. Too high, repair the transmission control valve; too low, check the converter relief valve and seal ring.
Manual Section: Transmission Troubleshooting p. 59Cab gauge shows transmission control pressure reading too low at all speeds
Check control pressure first; if it reads good, replace the cab gauge. If low, check lubrication pressure per page 59. Low lube pressure means run the pump test: low pump pressure, replace the pump; good, replace the gearbox. Good lube pressure sends you to the control time test; too long, test the pressure control valve and replace the valve or control unit.
Manual Section: Transmission Troubleshooting p. 59Power steering on the loader, steering wheel has a heavy feel when turning
Check reservoir oil level and add oil if low. Before opening the cap, turn the engine off, allow oil to cool and loosen the cap slowly (page 7). Test steering pump relief pressure against 185+5 kg/cm2 per page 48; low pressure from a broken pump means replace it. Clean, repair or replace a stuck steering valve, fill the steering gearbox to proper level and replace damaged gearbox bolts and nuts, per page 171.
Manual Section: Steering System Troubleshooting p. 171Loader hydraulics give slow bucket and boom movements and weak upward boom travel
Check reservoir oil level and fill to the specified level; turn the engine off, let oil cool and loosen the cap slowly first (page 7). Tighten intake connections and clean a dirty filter or intake line per page 235. Test main pump relief pressure against 195+5 kg/cm2 (page 48) and adjust if incorrect; clean or replace a sticking relief valve cartridge. Then suspect worn pump internals or worn cylinder seals.
Manual Section: Hydraulic Cylinder Troubleshooting p. 235Boom cylinder drifts and raised bucket drops while the loader control valve sits in neutral
Tighten loose pipes and joints first. If the boom still settles, check for a worn plunger in the control valve, a stuck overload relief valve with a worn seat, or a worn piston seal, per page 236. Before opening any valve or piping, securely brace the lift arm (page 8), and release accumulator pressure before loosening pilot lines, since a charged accumulator will lower a raised attachment (page 7).
Manual Section: Hydraulic Cylinder Troubleshooting p. 236Front or rear axle differential leaking gear oil around the carrier and seals
Inspect the differential carrier bolts and tighten any that are loose; replace the gasket if it is damaged. Clean or replace a clogged breather vent, and replace a worn or damaged oil seal per page 190. If the leak is coming from the wheel hub instead, tighten the loose bolts on the planetary gear set housing.
Manual Section: Axle Troubleshooting p. 190Frequently Asked Questions
What are the hydraulic pressure specifications for the main pump on the MEGA 300-III?
The relief cartridge for the main pump must open at 195+5 kg/cm² (2,845+70 psi). You can adjust this by loosening the locknut on the relief valve cartridge and turning the screw clockwise to increase pressure or counterclockwise to decrease it. p. 48
How do I test the hydraulic pressure on a Daewoo MEGA 300-III?
To test the main pump pressure, attach a gauge to Port 1 as shown in Figure 3-45. The relief cartridge for the main pump must open at 195+5 kg/cm² (2,845+70 psi). p. 48
What are the replacement specifications for hydraulic cylinder seals and O-rings on the Daewoo Mega 300-III?
Hydraulic cylinder seals should be replaced periodically, and you should check the cylinder drift rate at regular intervals. Overhaul seal kits are available through Daewoo, and maximum allowable drift rates are included at the end of the Hydraulic section in the Shop Manual. p. 14
What is the cylinder head bolt torque spec for the D2366T engine in the Daewoo Mega 300-III?
The final torque for the cylinder head bolts is 24.5 kg m (177 ft lb). The tightening procedure requires pre-lubricating the bolts with clean engine oil and tightening them in a specific sequence, first to 15 kg m (108 ft lb), then to 20 kg m (145 ft lb), and finally to the specified torque. p. 262
What is the correct valve clearance for the D2366T engine in the Daewoo Mega 300-III?
The valve clearance on a cold engine for both intake and exhaust valves is 0.3 mm (0.012"). p. 253
How quickly can I access this Daewoo Mega 300-III manual after buying?
You get a 277-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Can I print specific sections of this Daewoo Mega 300-III Shop Manual?
Yes. Many mechanics print the section they need for their own shop and bring it to the bench.
