Mitsubishi FGC15K–FGC30K Forklift & FG20–FG35A Engine Manual Set 2002–2005 (P/N 99719-70150)

The chassis publication covers truck-side work and refers engine servicing to the companion engine and applicable LPG books. The options supplement is designed for use with the chassis and mast manual.

FG20–FG35A coverage is limited to the engine manual. It does not extend the FGC chassis, mast, transmission, axle, or hydraulic procedures to those four FG models. Both engine books describe work with the engine removed; FGC engine removal and installation are covered separately in the chassis publication.

PDF Search, Bookmarks and Diagram Detail

Search and wiring detail: Most chassis and LPG supplement pages support text search. The two engine books and options supplement do not. All six PDFs have bookmarks with filename-style labels. Small wiring labels require zooming; some component labels in the S-15G wiring schematic overlap symbols.

The ZIP contains 6 printable PDFs totaling 870 pages, including 6 original title pages, 26 blank pages, and one repeated page in the LP-gas supplement. Original introductory material and contents pages are included in these totals.

Power Train, Mast and LPG Service Coverage

The selected topics below are examples from the publications, which also include battery specific-gravity checks and LP-gas fuel-selection guidance.

• Engine bench repair: Step-by-step procedures for timing-belt work, cylinder-head and valvetrain service, pistons, crankshaft, cylinder block, lubrication, and cooling components.

• Powershift transmission: Power-train removal, oil-pump and clutch-pack service, control-valve overhaul, hydraulic pressure testing, stall checks, and acceleration testing.

• Axles, brakes and steering: Reduction-differential setup, rear-axle and steering-cylinder overhaul, master-cylinder and wheel-brake service, bleeding, and steering-gear repair.

• Hydraulics and masts: Pump and control-valve repair, flow-regulator and cylinder checks, plus removal, reassembly, and adjustment for simplex, duplex, and triplex masts.

• Electrical and LPG diagnosis: Chassis wiring, S-15G system checks, Spectrum DTC charts, MIL/OBD testing, diagnostic data streams, and connector-level fault tracing.

• Factory options: Installation instructions for lighting, warning devices, additional oil filtration, enclosed alternators, axle configurations, and air-cleaner upgrades.

Suited to forklift technicians familiar with the systems being serviced and equipped for lifting, precision measurement, component overhaul, and fuel-system diagnosis.

4G63/4G64 Overhaul and Cooling

Engine procedures include hydraulic lash-adjuster bleeding and leak-down testing, piston-pin removal and installation, bearing-clearance measurement, and crankshaft-bearing selection. Separate sections address the carburetor, air governor, starter motor, alternator, and distributor.

The base engine book identifies a cylinder-block revision from engine serial number 4C1709-up, with corresponding changes to the crankshaft, center main-bearing choices, and thrust bearings. Its compatibility notes explain which replacement components belong together.

Truck-side cooling work includes radiator removal and installation, fan-belt inspection, and tension adjustment. The engine publications add water-pump service and lubrication-system references.

Transmission, Axle and Brake Work

Transmission instructions extend to input, output, and idler shafts, clutch plates and return springs, inching-pedal adjustment, and clutch-valve testing. Torque-converter removal and oil-pump service are included; the welded converter unit itself is not disassembled.

The pressure and stall-test information helps distinguish engine-output problems from hydraulic-control or internal transmission faults. Component weights and special-tool references also help a workshop plan power-train removal and bench work.

Axle setup includes bearing preload, reduction-gear backlash, face runout, and tooth-contact evaluation. Brake sections add wheel-cylinder inspection, automatic-adjuster checks, manual adjustment, fluid-line bleeding, and final operational testing.

Assembly notes address clutch-plate combinations and thrust-washer oil-groove orientation; the differential instructions warn that changing the original pinion shim can produce incorrect tooth contact and risk gear damage.

Hydraulic Cylinders and Mast Setup

Cylinder procedures distinguish simplex and triplex second cylinders, duplex and triplex first cylinders, and duplex second cylinders. Separate assembly drawings and service-data entries accompany seal replacement, relief-pressure checks, flow-regulator inspection, and cylinder-drift diagnosis.

Mast coverage identifies 3A15B/3A25B/3A30B simplex, 3B15C/3B25C/3B30C duplex, and 3C15C/3C25C/3C30C triplex assemblies. Configuration-specific instructions address lift-bracket and mast rollers, shim selection, mast-strip clearance, chain tension, fork inspection, tilt angle, and lift-cylinder stroke.

Hydraulic valve housings and spools are matched components; uneven tie-bolt tightening can distort the housings and restrict spool movement.

LPG Systems and Electrical Fault Tracing

The D-series LPG material covers the tank, vacuum fuel lock, converter/vaporizer, mixer/carburetor, leak testing, and adjustment. It also includes the S-15G CARB Tier 1 system for 2001–2002 applications. The E-series EPA supplement describes the 2004 fuel-system architecture.

EPA coverage explains ECM control, drive-by-wire throttle, the low-pressure regulator, and fuel and pressure trim valves. Related sections address TMAP, heated oxygen sensing, crank timing input, the catalytic muffler, and closed-loop fuel control.

Chassis electrical content includes the console box, combination meter, anti-restart starter switch, lighting, and fuse circuits. LPG diagnosis adds MIL/OBD checks, laptop data-stream and graphing procedures, connector views, and on-vehicle harness repair.

Visual references include the Transmission Hydraulic Circuit, chassis Electrical Schematic, and Schematic of Hydraulic System. Simplex/duplex/triplex mast assembly views, the S-15G Fuel System Wiring Schematic, and Closed Loop Control Schematic provide further system detail.

LP-gas tank and high-pressure component work requires appropriately qualified personnel and certified shops.

Option Kits and Workshop References

The options book covers rear combination and work lamps, a warning strobe, reverse buzzer, mirror, and auxiliary torque-converter oil filtration. Other installations include enclosed-alternator, axle-breather, wide/semi-wide axle, dual-element air-cleaner, and dust-indicator kits, within its specified C-series serial ranges.

Transmission tool references include piston tool 91268-07100, pressure-gauge kit 64309-17701, and connector 91268-00400. Hydraulic control-valve testing references pipe 64309-16300 and connector F4540-06300.

Engine references include oil-pan remover MD998727 and piston-pin setting tool MD998780. The EPA supplement specifies a hand-held diagnostic scanner and ITK-1 fuel-pressure test kit.

Service tables provide component torques, test pressures, fluid capacities and specifications, wear limits, clearances, maintenance and lubrication charts, component weights, and inspection guides.

Follow the manual’s support, pressure-release, battery-isolation, and lifting precautions when working with raised masts, heavy assemblies, LPG, hot parts, and hydraulic, brake, or electrical systems.

A Preview of Clutch and Differential Inspection Data

For the covered FGC powershift transmissions, clutch friction-plate thickness is specified at 2.6 ± 0.1 mm, with a 2.2 mm service limit.

Differential gear-to-pinion backlash is listed at 0.18–0.23 mm standard, with a 0.5 mm service limit. These values accompany the internal inspection and reassembly information.