Description

Clark-hurth SM 643, PWD 30-40SE, HWD 30-40SE Service Manual

You’ve got a Clark-hurth SM 643 or a PWD 30-40SE on the lift, and the service manual you grabbed from some third-party site has wiring diagrams that look like a kid drew them. I’ve seen that. Wasted hours tracing lines that don’t exist. This is the real deal: the Clark-hurth SM 643, PWD 30-40SE, HWD 30-40SE Service Manual that Clark printed for its dealer network. 206 pages, factory-bound, with every spec Clark intended for these trucks. No aftermarket interpretation.

Working on these industrial lift trucks without the right documentation is a gamble. You might guess the commutator undercutting depth or the brake switch adjustment, but guessing costs time and parts. This manual is organized by Groups – think of them as chapters – starting with periodic service and moving through every system. Clark arranged it that way so a technician can hop to the section needed without flipping through irrelevant pages.

Group 40 Truck Specifications: Torque Values for SM 643, PWD 30-40SE, HWD 30-40SE

Torque specs live in Group 40, where Clark lists every fastener value for the drive unit, brakes, and hydraulic system. You want the ring and pinion end play adjustment? That’s in Group 20. The specifications section gives you the numbers straight from the factory floor. I’ve seen aftermarket manuals list a generic torque for a 5/8-inch bolt that doesn’t account for the grade. Group 40 breaks it down by application – battery, brake, electrical, tires, and truck service weights. That level of detail is why you pay for a factory manual.

Wiring Diagrams for PWD and HWD Models

Group 14 is where the wiring lives. Separate diagrams for the PWD and HWD variants. If you’ve ever tried to trace a short in a lift truck using a photocopy of a photocopy, you know the value of clean, printed schematics. The manual shows every connection from the battery to the controller to the drive motor. And Group 19 covers the controller wiring in even more depth – including contactor, switches, and other hardware. Do not trust an aftermarket diagram for the HWD controller; Clark’s own document has the correct pinouts.

Group 20 Drive Unit – Disassembly and Reassembly

This section is the backbone of the powertrain service. Starts with removal, then disassembly, cleaning and inspection, and reassembly with adjustment specifications. If you skip the cleaning and inspection step before reassembly, you’ll be pulling that drive unit again in six months. Clark includes ring and pinion end play specs – that’s not something you guess. The manual also covers installation of the unit back into the truck. For anyone working on the SM 643 or the PWD/HWD 30-40SE models, this group alone is worth the price of the manual.

Group 19 Controller Diagnostics and Troubleshooting

Two controller sections here – PWD and HWD. Both start with an overview, then connections, programmable parameters, installation checkout, and bench testing with the 1307 programmer. The diagnostics sections include a troubleshooting chart and LED diagnostics. If the truck won’t move, the LEDs tell a story. Group 19 is where you learn to read that story. It also covers the Special Program Menu and the Diagnostics Menu. I’ve had to walk a junior tech through a dead controller over the phone; having this manual in front of him would have saved me an hour.

3 Sections for Electric Motor Service

Group 16 covers the electric motor in detail: maintenance, inspection procedures, disassembly, cleaning and inspection, commutator undercutting, testing, and frame and field service notes. Commutator undercutting is one of those procedures that looks easy on YouTube but requires specific mica depth and clean edges. This manual gives you the factory method. The assembly and testing section ensures you don’t put a motor back together with a burred commutator. If you’re rebuilding a drive motor on a PWD 30-40SE, you need this.

What Does the Manual Cover for Lift Cylinders?

Group 34 – lift cylinder removal, block lift frame, disconnect hoses, disconnect cylinder base, disassembly, inspection, and reassembly. Each step is spelled out with the order of operations. For example, before disconnecting hoses you block the lift frame. That’s a safety step that aftermarket manuals often gloss over. The inspection section tells you what to look for in the cylinder bore and piston seals. Not generic “inspect for wear” – specific wear limits from Clark.

If you work on these trucks, you likely also handle other Clark-hurth models. The Spicer Clark-hurth HR Service Manual – Factory Specs for Heavy-Duty Transmission covers a different series but follows the same factory documentation standard. For the 55A series, the Clark-hurth 55A SERIES II Service Manual – 136 Pages of Factory Specs is a solid companion. And if you need the SM-715 or TMX/EPX models, the Clark-hurth SM-715, TMX12-25, EPX16-20s 2007 Service Manual – 502 Page OEM Facto is another thick binder worth having.

The drive unit in these trucks is essentially a heavy-duty Manual Transmission with reduction gearing. Understanding how a Manual Transmission works helps when you’re setting ring and pinion end play. But don’t let that fool you – the Clark-hurth system has its own adjustments that only this manual spells out.

Does this service manual include the PM check sheet from Group PS?

Yes. The Periodic Service section includes the PM Check Sheet, visual inspection procedures, operational tests, and the maintenance schedule with determining intervals. That’s Group PS, Sections 1 through 3.

Are both PWD 30-40SE and HWD 30-40SE covered in the same book?

Yes.

What kind of troubleshooting data is in Group 19 for the controller?

Group 19 provides two full troubleshooting charts – one for the PWD controller and one for the HWD controller. Each chart lists symptoms, possible causes, and corrective actions. The LED diagnostics section decodes flash patterns so you can pinpoint a failed contactor or a bad speed sensor without replacing parts at random. Also included are the 1307 programmer menus, special program menu, and diagnostics menu. If the truck is dead on the dock, you can work through the chart step by step and find the fault in under 30 minutes – if you have the manual. This is not a generic “check wiring” guide; it’s a systematic approach.

Is this a photocopy or an original OEM document?

This is a scanned PDF from the original Clark publication, not a reprint. The file includes all 206 pages as they appeared in the dealer manual, with the copyright notice stating “Intended for CLARK dealers only.”

Bottom line: if you’re tearing down a Clark-hurth SM 643 or rebuilding the drive unit on a PWD 30-40SE or HWD 30-40SE, you need the factory data. Don’t trust a third-party summary for ring and pinion end play or commutator undercutting. Access the Factory Manual and get the same information Clark’s own techs used.