Mitsubishi FG15K, FD15K, FG18K, FD18K, FG20K, FD20K, FG25K, FD25K, FG30K, FD30K, FG35K, FD35K Forklift Service Manual (P/N 99729-74120)

• Gasoline FG coverage: FG15K (EF31A-60001-up), FG18K (EF31A-85001-up), FG20K (EF17B-15001-up), FG25K (EF17B-65001-up), FG30K (EF13D-45001-up), and FG35K (EF13D-65001-up).
• Diesel FD coverage: FD15K (EF16B-65001-up), FD18K (EF16B-85001-up), FD20K (EF18B-15001-up), FD25K (EF18B-65001-up), FD30K (EF14C-45001-up), and FD35K (EF14C-65001-up).
• Powertrain and Powershift work: Covers engine/transmission removal and installation, transmission disassembly and reassembly, pump and control-valve service, hydraulic-pressure testing, inching-pedal adjustment, clutch-valve testing, and the start-acceleration test.
• Axle, brake, steering, and hydraulic repair: Includes front axle and reduction-differential setup, tooth-contact pattern adjustment, rear axle and steering-cylinder repair, brake bleeding and adjustment, steering-control-valve overhaul, hydraulic pump testing, and lift/tilt-cylinder service.
• Electrical and control diagnosis: Details the console box, combination meter, anti-restart starter switch, fuse and lighting circuits, battery service, the Advanced Control (AC) System, checker-to-controller connections, controller LED indications, hydraulic-pressure-transducer and lift/tilt-lever inputs, solenoid-control-valve troubleshooting, and separate gasoline/diesel electrical schematics.
• Mast configurations and setup: Documents Simplex, Duplex, and Triplex masts, with mast and lift-bracket removal, disassembly, inspection, reassembly, chain and roller checks, clearance adjustments, tilt-angle setup, and lift-cylinder stroke adjustment.
• 4G63/4G64 gasoline-engine repair: Covers engine adjustment, timing belt, fuel and lubrication systems, cylinder head and valves, rocker arms and camshaft, pistons and connecting rods, crankshaft and cylinder block, carburetor, air governor, distributor, alternator, and starter motor.

Exact Coverage and Set Makeup

This Mitsubishi factory service manual set is suited to trained, experienced forklift technicians who can safely handle heavy assemblies and use hydraulic test equipment, electrical meters, lifting gear, and the specified service tools. It contains 492 PDF pages across two publications: the 379-page chassis/mast manual, Mitsubishi Pub. No. 99719-53120, and the 113-page 4G63/4G64 gasoline-engine manual, Mitsubishi Pub. No. 99729-74120.

The chassis volume covers the listed 1.5- to 3.5-ton FG gasoline and FD diesel trucks and identifies the 4G63/4G64 gasoline and S4Q2/S4S diesel configurations. Its axle data and repair illustrations distinguish the 1.5- to 2.5-ton designs from the 3- to 3.5-ton versions where the hardware differs. The included engine volume applies to 4G63 and 4G64 engines numbered AA0001-ZZ9999-up. Diesel-truck chassis, mast, transmission, hydraulic, brake, steering, and electrical work is covered, but internal diesel-engine repair requires a separate engine manual and is not included in this set.

Controls, Diagnostics, and Shop Procedures

“AC” in this manual means Advanced Control System, not air conditioning. That section goes beyond a wiring overview: it identifies the controller and connectors, explains checker hookup, presents case-based fault isolation, and covers emergency mast movement, harness-connector cleaning, and solenoid-control-valve troubleshooting. The main volume also provides removal, inspection, adjustment, reassembly, and operational-test coverage for the Powershift transmission, differential, service brakes, steering system, hydraulic equipment, and all three mast families.

The gasoline-engine volume supplies the internal repair depth that the chassis book intentionally leaves to a separate engine publication. Along with overhaul procedures, it provides engine-specific service limits, component torque tables, sealant locations, inspection data, and troubleshooting charts. The special-tool section identifies tools by Mitsubishi number and purpose, including the MD998440 lash-adjuster leak-down tester, MD998441 lash-adjuster retainer, and MD998375 crankshaft front oil-seal installer.

Diagrams, Specifications, and Repair Cautions

Diagnostic references include the Electrical Schematic (Type: Gasoline), Electrical Schematic (Type: Diesel), the Powershift Hydraulic Circuit, the lift/tilt Hydraulic Circuit Diagram, the steering-system schematic, and front-axle/reduction-differential section views with tooth-contact patterns. Exploded assembly drawings support transmission, axle, brake, steering, hydraulic, mast, and engine repair without replacing the written inspection and setup procedures.

Service-data sections provide maintenance charts, standard and special tightening-torque tables, periodic-replacement parts, fuel and lubricant specifications, refill capacities, approximate major-component weights, wear limits, clearances, adjustment data, pressure-test specifications, and electrical test information. The engine manual also flags real assembly risks: an oversized formed-in-place gasket bead can restrict a fluid passage, while a thin or broken bead can leak. During alternator repair, inserting a prying tool too deeply between the bracket and stator can damage the stator core.

Before repair work, support the truck and mast correctly, lower or block raised components, release stored hydraulic pressure, and isolate electrical power as directed by the manual.