Description

Doosan D50S-5, D60S-5, D70S-5, D80S-5, D90S-5 2007 Technical Manual

I’ve seen too many guys lose a Saturday because they used a generic manual that listed wrong torque values or skipped the shimming procedure. If you’re working on a Doosan D50S-5, D60S-5, D70S-5, D80S-5, or D90S-5 from the 2007 model year, you need the real factory book – not a scanned PDF that’s missing pages. This 69-page Technical Manual (part of the Power Train series) gives you the exact specs Doosan wrote for the two-speed transmission, drive axle with OCDB and shoe brakes, and the converter. No reprints, no third-party interpretation. Page 5 has the general tightening torque table – that’s where you start before you touch any bolt.

This manual came off the press in September 2007. It covers the D50S-5 through D90S-5, plus the G50S-5, G60S-5, G70S-5 variants (gas/LP models). The content is broken into Specification, System Operation, Testing & Adjusting, and Disassembly & Assembly. If you’ve ever had a transmission that shifts late or a brake drum that’s out of round, you’ll find the factory procedures to fix it right. The official Doosan manual is the only source for these numbers – aftermarket manuals drop the detailed hydraulic schematics and the shimming instructions. Don’t take shortcuts on a 10,000-pound forklift.

General Tightening Torque on Page 5

Every bolt on this machine has a specified torque, and the manual lists them in foot-pounds. The table on page 5 covers fasteners from M6 to M24, grade 8.8 and 10.9. If you’re replacing a transmission pump or mounting the drive axle, those numbers are non-negotiable. I’ve seen stripped threads from using “good enough” settings – that’s a day of drilling and heli-coiling you don’t need. The manual also includes drive axle specs on page 6, torque converter data on page 7, and transmission pump flow rates. Write the torque values on the shop wall if you have to, but use the book.

Power Flow: Low Speed and High Speed Forward

The power shift transmission uses a planetary system with two speed ranges. Pages 13-16 show power flow for low-speed forward, high-speed forward, low-speed reverse, and high-speed reverse. If you’re chasing a clutch pack failure, the hydraulic schematic on page 18 (Transmission Control Valve) shows exactly which ports supply each clutch. This isn’t a generic diagram – it’s the factory cross-section and valve body layout. You can trace the pressure drop from the pump to the clutch and find the leak. Follow the troubleshooting checklist on page 23 before you open the case. That saves hours of pulling a transmission that might only need a seal.

Testing and Adjusting: Transmission Pressure and Converter Stall

The manual’s Testing and Adjusting section (pages 23-32) is where most DIY guys and even some pros screw up. Page 26 has the check list from pressure test – you need a gauge that reads to 300 psi. The transmission pressure specs are on page 28; the converter stall test procedure is on page 29. I’ve seen people skip the stall test and then wonder why the inching pedal won’t hold. The wheel brake adjustment (page 30) and inching pedal adjustment (page 32) are step-by-step with measurements in inches. If you don’t have the factory procedure, you’ll get the clearances wrong and burn up the brake linings in a month. For a deep dive into the power train disassembly, check the Doosan Power Train Transmission 3WG94 Disassembly & Assembly manual – it covers the same transmission family with more tear-down detail.

Disassembly and Assembly: Drive Shaft and Transmission Control Valve

The Disassembly and Assembly section starts on page 35 with the drive shaft and universal joint. Universal joint replacement is straightforward if you have the right snap-ring pliers and know the bearing cap orientation – the manual shows it. Pages 36-39 cover separating the engine, torque converter, and transmission. You must support the transmission with a jack that centers on the bell housing; otherwise you’ll bend the converter pilot. The transmission control valve removal (page 40) requires you to note the spring positions – the manual has a cross-reference table. Do not try to rebuild the valve body without the hydraulic schematic on page 18. After you’re done, you need to check the Doosan Diesel Engine DB58S 5.8 Liter Service Manual if your D80S-5 has that engine – the coupling specs between engine and converter are in that book.

Safety Information: Read Before You Touch Anything

Page 3 has the full safety warning – not a generic boilerplate. Doosan warns that improper lubrication, maintenance, or repair can cause injury or death. The manual emphasizes that you must have the necessary training, skills, and tools. If you use a tool or procedure not recommended by Doosan, you must verify it’s safe. The manual also states that specifications can change; always get the latest info from a Doosan dealer. For electrical and hydraulic safety, the Manual Transmission article on Wikipedia covers the basics of gearbox operation, but it doesn’t replace this factory manual. The real book includes torque converter charge pressure and wheel bearing preload – numbers you won’t find anywhere else.

What This Manual Covers (and What It Doesn’t)

This 69-page technical manual covers power train only – transmission, drive axle (OCDB and shoe brakes), and the torque converter. It does not cover the engine, electrical system, or hydraulic attachments. For engine repair, get the Doosan G643E G643 LP Engine Service Manual if you have a gas model. The manual includes the entire Index (page 3) and Specification chapter with drive axle mounting torque, differential specs, wheel bearing adjustments, brake drum diameter (page 10), and U-joint dimensions. If you need the complete breakdown of the two-speed transmission, the Manual Transmission general theory page can help understand the concept, but it won’t tell you the clutch clearance for the D70S-5. Only the factory manual has that.

Audience Fit: Forklift Mechanics, Fleet Owners, DIY Operators

If you’re a forklift mechanic in a warehouse, this manual saves you from flipping through three different aftermarket binders to find the inching pedal adjustment spec (page 32). Fleet owners who maintain a dozen D-series trucks need one source for all models. DIY owners who bought a used D50S-5 for the farm – you can do the brake adjustment and transmission pressure test yourself, but only if you follow the factory sequence. The manual assumes you have basic mechanic tools and a pressure gauge. It does not assume you’re a Doosan- certified tech, but it does expect you to follow the safety warnings. If you ignore the converter stall test procedure (page 29), you risk damaging the stator support. That’s a $600 part you could have avoided wrecking.

Source Validity: OEM Factory Manual vs Aftermarket

This is an authentic Doosan publication printed in 2007 (SB4274E00). It contains the original illustrations, torque tables, and hydraulic diagrams. Aftermarket manuals often crop the page numbers, drop the safety section, or redraw the schematic incorrectly. I’ve seen a third-party manual that showed the transmission control valve ports reversed – that would send pressure to the wrong clutch and cause immediate failure. The factory book is the only one you can trust for critical jobs like transmission shimming (page 30) or differential bearing preload. The PDF is a direct scan of the physical manual; every page is readable. You can zoom in on the torque converter cross-section on page 7 and read the pump flow numbers.

Does this manual cover the two-speed transmission?

Yes. Pages 12-16 show power flow for all four modes (low/high forward/reverse). The transmission control valve is detailed on pages 17-18.

What torque values are listed?

General tightening torque is on page 5 for bolts M6-M24. Drive axle mounting torque is on page 8. Wheel bearing preload is specified in inch-pounds. The manual also gives brake drum diameter limits (page 10) and U-joint specs. All values are in imperial units (ft-lb, in-lb).

Is this a genuine OEM manual or a reprint?

This is the original Doosan PDF from 2007, direct from the factory. It is not a reprint or a scan of a copy. The file name matches the OEM part number SB4274E00. You get the safety information, spec tables, and full hydraulic schematics that aftermarket manuals cut out.

Can I use this manual for the G50S-5 gas model?

Yes. The manual explicitly covers the G50S-5, G60S-5, and G70S-5 with LP or gas engines. The power train components (transmission, drive axle, brakes) are identical to the diesel D-series. For engine-specific work, you’ll need the separate engine service manual.

This Technical Manual puts the factory procedures on your bench – from torque values to shimming diagrams. If you’re rebuilding the transmission, checking the differential, or adjusting the brakes, you need the book that Doosan wrote for the technicians who built these machines. Stop guessing and start measuring. Access the Factory Manual and keep it on your tablet or print the critical pages. Your torque wrench and your safety depend on it.