2006–2012 JLG G6-42A / G9-43A / G10-43A Telehandler Service Manual (P/N 31200151)

This service manual for the 2006–2012 JLG G6-42A, G9-43A and G10-43A telehandlers, P/N 31200151, revised August 9, 2012, covers machine maintenance, fault diagnosis and repair procedures across the documented engine and serial-number configurations.

• Boom service: Assembly and section removal, extend/retract chain replacement and tension adjustment, wear-pad inspection, Quick Switch service and boom-mounted winch removal.

• Cab and controls: Throttle and brake pedal removal, joystick assemblies, heater service, steering components and associated electrical circuits.

• Drivetrain and brakes: Front and rear axle removal, drive-shaft inspection, transmission replacement, brake testing and bleeding, and manual park-brake release.

• Engine installation: John Deere, Perkins and Cummins component identification, routine maintenance, engine removal and installation, cooling-system service and symptom-based troubleshooting.

• Hydraulic repair: Circuit pressure checks, pump replacement, main control valve disassembly, steer select and outrigger valves, and hydraulic-cylinder inspection and resealing.

• Electrical diagnosis: Fuse and relay locations, wiring and starting circuits, component tests, engine-specific diagnostic information and JLG hand-held analyzer menus.

Suited to experienced service technicians who can use lifting equipment and hydraulic and electrical test instruments.

Boom Chains, Wear Pads and Attachments

Boom coverage includes complete assembly removal, section disassembly and model-specific chain tension adjustment. Separate procedures address chain replacement without removing the boom assembly, helping technicians determine whether the planned repair requires a full boom teardown.

The Temporary Extend Chain Bracket and Temporary Retract Chain Bracket drawings accompany the chain procedures. Quick Switch assembly service, boom head-mounted winch removal, wear-pad inspection and shimming receive their own instructions.

Cab Controls, Steering and Brake Service

Cab procedures cover throttle and brake pedals, joystick assemblies and heater removal. A/C coverage includes electrical circuits; the steering orbitrol valve is treated as a replacement assembly, with internal repair referred to the component supplier.

Brake coverage includes testing, bleeding, and manual park-brake release and reset. Follow the manual’s precautions for raised booms, stored hydraulic pressure and lifting heavy assemblies.

Axles, Drive Shafts and Transmission Replacement

Front and rear axle removal and troubleshooting cover Carraro and Dana configurations, including planetary wheel-hub maintenance. Internal axle repair refers to separate component manuals; drive shafts are factory balanced, with damaged assemblies replaced.

Dana-Spicer T12000 and ZF 4WG-92/98 transmissions: Procedures cover removal, installation, engine drive plates, thermal bypass valves and fault diagnosis. Internal transmission overhaul requires the separate Dana-Spicer or ZF repair manual.

Engine, Fuel and Cooling-System Work

John Deere, Perkins and Cummins sections identify engine components, including fuel injection pumps, and cover routine maintenance, engine removal and installation, and symptom-based troubleshooting. Internal engine repair is referred to separate manufacturer manuals.

Radiator, thermostat, oil-cooler, fuel-tank, air-cleaner and exhaust procedures support engine service. Lubrication tables specify fluids such as Mobilfluid 424 by application, with separate cooling, transmission and hydraulic-system capacities.

Hydraulic Circuits, Control Valves and Cylinders

The G6-42A Hydraulic Schematic and G9-43A/G10-43A Hydraulic Schematic accompany model- and serial-specific pressure-check tables. These help identify the matching test circuit when investigating lift, tilt, steering or outrigger faults.

Coverage includes main control valve disassembly, steer select and G10-43A outrigger control valves, implement-pump replacement and hydraulic-cylinder service, including the compensation cylinder. Internal implement-pump repair is referred to a JLG distributor.

Cylinder-rod surface damage can cause seal failure. Disturbing the main control valve’s preset relief settings alters circuit pressure and requires recalibration or a new relief valve.

Starting Circuits, Analyzer Menus and Fault Codes

Fuse and relay locations and Start Circuit diagrams distinguish the engine installations. The Variable Displacement Pump Schematic and JLG hand-held analyzer menus support pump-control diagnosis on later G9-43A/G10-43A configurations; analyzer diagrams also show joystick settings and calibration screens.

Engine diagnostics: Cummins tables list fault codes, SPN/FMI identifiers and warning lamps. Perkins coverage explains warning and shutdown indicators, while John Deere engine electrical troubleshooting is referred to a separate manual.

Joystick DTC tables address machine-control faults on the later G9-43A/G10-43A configurations, including affected functions and calibration-related faults.

A Sample of Boom Clearance and Chain Wear Limits

These boom measurements are a small selection of the manual’s adjustment and wear data. Other reference sections include SAE and metric fastener, hydraulic-hose and O-ring face-seal torque charts.

Wear-pad setup specifies total boom-section clearance of 0.070–0.130 in in both horizontal and vertical directions for the covered models.

Boom-chain inspection uses a replacement limit of 3% elongation against normal chain length. The measurement applies to the section traveling over the sheaves; the less-flexed chain ends can give misleading results.

Searchable Service Text and Zoomable Schematics

Finding procedures and circuit detail: Native text supports searching the service instructions, and bookmarks organize sections and subsections. Some drawing labels are not searchable; small hydraulic and wiring labels require magnification for comfortable reading.

One printable English-language PDF contains 244 pages: 234 pages across the service sections, eight front-matter pages and two closing pages. Covers and blank pages are included in that total; the separately referenced component manuals are not included.