Description

Doosan D20S-5, D25S-5, D30S-5, D33S-5, D35C-5 2007 Technical Manual

Let me tell you straight: if you’ve ever cracked open a aftermarket manual for a Doosan forklift and found torque specs that don’t match the hardware on your bench, you know the headache I’m talking about. This Doosan D20S-5, D25S-5, D30S-5, D33S-5, D35C-5 2007 Technical Manual is the real deal – 53 pages of factory-authored procedures for the power train. No generic reprints, no third-party guesses. Just the OEM data from 2007 that tells you exactly how to pull that transmission housing apart and put it back together without shaving splines or snapping bolts.

Transmission Disassembly and Assembly

The manual starts with the transmission, and it doesn’t waste space. You get the full breakdown: disassembly of the transmission housing on page 5, then the counter shaft (page 9), the input shaft (page 14), the output shaft (page 19), and finally the reassembly steps for the housing on page 20. Each section lists the required tools – no surprises like “use a press” without specifying the tonnage. One section I lean on hard is the valve assembly (page 26). That valve body can lock up a shift if you install a spring backward, and this manual gives the exploded view and clearance checks.

Drive Axle: From Shaft to Differential

Drive axle work on these D20S-5 models is straightforward when you follow the factory order. The manual walks you through disassembly of the drive axle (page 27), then the shaft (page 30), brake parts (page 31), hub (page 32), and the differential assembly (page 33). The bevel pinion adjustment on page 36 is the part that separates a lasting repair from a noisy one. You get the shim selection procedure and the preload spec – don’t skip it. I’ve seen guys ruin a crown wheel set by guessing the backlash. This manual gives you the numbers, not a range that covers three different models.

6 Special Service Tools You’ll Want Ready

Towards the back, pages 50–53 list the special service tools Doosan requires for these jobs. Puller sets, seal installers, bearing separators – the exact part numbers. You don’t need to buy a full dealer tool chest, but if you plan on doing more than one of these transmissions, you’ll want the bearing installer for the counter shaft. The manual doesn’t assume you have a machine shop; it tells you the tool and the method. For the clutch pack on the D30S-5, that tool list saves an hour of swearing.

Source Authenticity: OEM vs. Aftermarket

I’ve bought aftermarket manuals that claim to cover the D33S-5, and they combine procedures from a different year with mismatched bolt torque. This is the 2007 Doosan Technical Manual – the same binder the dealership techs used. You can see the part number SB4254E00 on the cover. The safety warnings (page 3) are straight from the manufacturer, not some generic liability page. When the manual says “WARNING: Do not operate without reading this section,” it’s because they tested the hazard. Aftermarket publishers don’t have that liability – and it shows in their shortcuts.

Does This Manual Cover the Fuel System or Engine?

No. This is strictly the power train: transmission, drive axle, and the associated disassembly/assembly procedures. If you need the engine service specs for the Doosan D20S-5, you’ll want the Doosan Forklift 2008 Service Manual or the Doosan Forklift D-Series Service Manual 2008 for the later updates. For this manual, you get the transmission internals and axle adjustments that keep the forklift pulling. If you’re rebuilding a Manual Transmission – yeah, it’s not automatic – this is your playbook.

What Torque Values Are Listed?

The manual doesn’t print a generic torque chart; it gives specific ft-lb values at each step. For the bevel pinion nut, you get the preload setting. For the transmission housing bolts, it lists the pattern and torque. The Doosan Forklift Service Manual 2008 might cover later models, but for a 2007 D25S-5, this 53-page document is the one you want. If you need detailed theory of operation, the Manual Transmission resources online can supplement, but the actual wrench-turning specs come from this OEM PDF.

Frequently Asked Questions

Does this manual include torque specifications for the differential?

Yes. Page 36 covers the bevel pinion adjustment, and the assembly section for the crown wheel (page 42) gives the backlash and preload values. You get the numbers, not a reference to a separate chart.

Will this work on a D35C-5 with a different transmission?

Check the model list on the cover. This manual covers D20S-5 through D35C-5 – same gearbox family. If your unit has a serial number outside that range, call Doosan with your VIN.

How many pages are the special tools section?

Pages 50–53. Four pages with part numbers and illustrations. Enough to order what you need before you start.

I’m a home-garage guy. Can I rebuild the transmission with basic tools?

You can do the disassembly with hand tools – sockets, pullers, a press for the bearings. The manual lists the special tools, but a savvy DIYer can substitute a bearing splitter and a hydraulic press. Don’t skip the torque wrench for the valve body bolts; the manual calls for 18–22 ft-lb on page 26. Start with the counter shaft disassembly on page 9 if you want a feel for the job before diving into the housing.

This manual isn’t a coffee-table book. It’s a 53-page factory document that shows you the order, the tools, and the safeties. If you’re pulling a transmission out of a D30S-5 this weekend, having this PDF open on your tablet beats flipping through three different repair blogs. Access the Factory Manual and get the right specs the first time.