Description

Doosan D35S, D40S 1997 Service Manual

Doosan built the D35S and D40S with a two-speed power shift transmission and either a 1004.4 diesel or a Vortec V6 gasoline engine. Each system has specific torque values you cannot eyeball. The Doosan D35S, D40S 1997 Service Manual is the only source for those numbers. Without it, you are wasting time and risking damage. This is a factory document, not a third-party rewrite. 866 pages of OEM data from Doosan itself.

866 Pages of Factory Documentation

You get PDF bookmarks for each major section: Engine, Power Train, Vehicle Systems, Operation & Maintenance. The manual includes GM Vortec V6 (4.3L) gasoline engine procedures, Bosch B1 alternator bench tests, and Nippondenso starter motor rebuilding specs. Every page matches what Doosan printed in 1997. No aftermarket condensation.

Torque Specifications – Start at Page 2

Torque values are the first thing I check before pulling a head bolt. Page 2 is the dedicated torque spec sheet. The manual warns that improper torque can cause failure or injury. That warning is not there to fill space. For the transmission, engine mounts, and hydraulic connections, you need those numbers. The Doosan P158LE P180LE P222LE PU158TI PU180TI 2008 Service Manual covers later models, but for the 1997 D35S and D40S, this is the one.

Engine Section: Diesel and Gasoline Overhaul

The engine chapter runs over 200 pages. It covers the 1004.4 diesel block (cylinder head, fuel injection timing) and the GM Vortec V6 (4.3L) gasoline engine. Both sections include disassembly, inspection, and reassembly with torque sequences. The Vortec section also shows the D & A (disassembly and assembly) for the G35S and G40S variants. If you are replacing a head gasket on the 4.3L, the manual tells you the bolt tightening pattern. I have seen too many warped heads from skipping that step.

Why the Two Speed Power Shift Transmission Section Is Critical?

The power train section includes the two-speed powershift transmission, differential, and drive axle. A common failure on these forklifts is clutch pack wear. The manual provides hydraulic pressure specs and shift timing adjustments. Without the factory procedure, you will burn up a reman unit. The transmission section also has its own torque chart for bell housing and converter bolts. I recommend reading the safety warnings in the Manual Transmission Wikipedia article if you need a refresher on basic gear train principles, but this manual has the specific Doosan data you need.

Hydraulic and Electric Schematics – Trace Problems Systematically

Vehicle Systems section includes hydraulic system schematic and electric system schematic. The hydraulic schematic shows flow paths for mast tilt, lift, and steering. The electric schematic covers the ignition, starter, alternator, and safety interlocks. Page numbers are in the PDF bookmarks. When you have a no-start condition, start with the electric schematic, not parts swapping. The Manual Transmission external reference is useful for understanding gear ratios, but for the D35S/D40S electronics, stick to the factory schematic.

Safety Warnings You Cannot Skip

The manual opens with a safety section (SB2003E00). Doosan explicitly states: “Improper performance of lubrication or maintenance procedures is dangerous and could result in injury or death.” They cover lifting heavy components (23 kg or more) with a hoist, hot surfaces, and cover plate removal. Those warnings are there because someone got hurt before. Read them.

Does this manual cover the GM Vortec V6 engine used in other equipment?

Yes, but only for the Doosan D35S and D40S installations. The Vortec section is specific to the G35S and G40S variants.

Can I find wiring diagrams for the charging system?

The electric system schematic includes the Delco Remy CS-121 alternator and Bosch B1 alternator wiring. Page location varies by PDF viewer, but the bookmark is labeled “Electric System Schematic.”

What if I need the shift pressure specs for the two-speed transmission?

The Power Train section (SB2038E01) contains pressure test ports and adjustment procedures. No other source has these values. You must use the factory specs.

How do I know the PDF is legitimate?

This is a direct scan of the original Doosan 1997 service manual, form SB2056E. The PDF bookmarks match the printed TOC. There is no OCR with missing data. What you see is what Doosan wrote.

Stop guessing torque values and digging through forum threads. The Doosan D35S, D40S 1997 Service Manual puts the factory procedure on your screen. Access the Factory Manual and keep it on your tablet next to the forklift. Your transmission and engine will thank you.

Need coverage for other Doosan models? Check the Doosan D33S, D35C, D20/25/30S, G20/25/30P-5 2008 Service Manual and Doosan V2403 Service Manual – Factory OEM Specs for Marine Engine.