Description

ZF HP 502, HP 552, HP 592, HP 602 Repair Manual

I see this all the time: a guy buys a bus or a fire truck with a ZF Ecomat 2, gets a reman unit from a supplier, and then starts throwing wrenches at it with a generic service manual he found online. Ends up with a stripped bolt or a converter that leaks because he torqued the cover plate to some number he guessed at. That’s why you need the ZF HP 502, HP 552, HP 592, HP 602 Repair Manual—not a copy, not a reprint, but the actual OEM document straight from the factory floor in Germany. 334 pages of procedures that ZF themselves wrote for their own technicians.

What You Get with 334 Pages of Factory Content

Open this manual and the first thing you see is a table of contents that covers every system in these Ecomat 2 transmissions: the converter, the retarder accumulator, the hydraulic control unit, the mechanical planetary sections. Each chapter tells you exactly how to remove, install, dismantle, and assemble—in that order, not jumping around. The ZF Ecomat 2 comes in 4-speed, 5-speed, and 6-speed versions, and the book gives you separate cross-sections and adjustment data for each. 334 pages means there’s room for the details most aftermarket books skip: the spring table, the expendable material list, the special tool numbers. You won’t find a single line of fluff.

Tightening Torques and Adjustment Data

Need the torque for the cover plate bolts? That’s on the Tightening Torques page (page 10). Need the axial bearing end play spec for the ZFW 380-30 converter? That’s in the Adjustment Data section (page 15). These are numbers that ZF certified in 2000-09, not numbers some third-party writer pulled off a forum. I’ve rebuilt half a dozen HP 502 units using this manual—every torque value matched what my snap-on wrench read. If you skip this section and use a generic chart, you’ll find out when the oil pan starts weeping at the seam.

Converter Rebuild: ZFW 380-30 and ZFW 360-10

The converter chapter alone is worth the price. It walks you through two converter variants: the ZFW 380-30 and the ZFW 360-10. You get dismantle procedures for the stator, the turbine wheel, and the circuit cover—each with its own subsection so you don’t mix up parts. The manual tells you how to measure converter end play and installation dimension before you button it up. Then it shows you how to check converter leak-tightness. I’ve seen shops ruin a $3,000 converter because they didn’t measure the axial bearing end play properly. Don’t be that shop. Follow section 4.4.2 and 4.4.4 exactly.

Is This Manual Right for Your Transmission?

If you’re working on an HP 502, HP 552, HP 592, or HP 602—whether it’s in a municipal bus, a refuse truck, or a fire apparatus—this is the document you need. The manual covers Stage 3 transmissions with part number 4149 751 604. It does not cover earlier versions or the Ecomat 1. For those, you’d want the ZF 6WG 310 1999 Repair Manual – Factory Specs for 6WG 310 or the ZF HFS 507, GP 18, GP 20, GP 21 2004 Repair Manual – Factory Specs. But for the HP 502 series, this is it. The manual assumes you have a transmission jack, a set of snap-ring pliers, and a torque wrench that’s been calibrated within the last year. Beginners can use it if they follow each step in order—don’t start dismantling the hydraulic control unit (chapter 8) until you’ve read the safety warnings on page 7.

Factory Documentation vs. Aftermarket Reprints

I’ve seen enough aftermarket manuals to know they cut corners. They’ll give you a torque spec but skip the note about applying threadlocker. They’ll show a wiring diagram that’s a photocopy of a photocopy. This ZF manual is a first-generation digital scan of the original printed in Germany. The copyright page (page 2) makes it clear: no reproduction without approval. What you get is the same content ZF sends to its authorized service centers. If you want an overview of the automotive repair industry standards, check Automotive Industry Overview on a trusted site, but for this transmission, stick with the factory source. The ZF HP 500, HP 590, HP 600, HP 502, HP 592 2004 User Manual – Factory Specs covers some overlapping models, but for the full rebuild, this 2000 manual is more detailed on the converter and hydraulic unit.

Frequently Asked Questions

Does this manual cover the retarder accumulator removal and assembly?

Yes, chapter 2 covers the retarder accumulator in full: removal, installation, dismantle, and assembly. Four subsections with step-by-step instructions.

What torque values are listed?

Page 10 has a dedicated tightening torques table. It covers all common fasteners on the HP 502/552/592/602 transmissions, including oil pan bolts, cover plate screws, and converter housing bolts. Specs are in Nm and include notes if threadlocker or lubrication is required.

Can I use this to rebuild the hydraulic control unit?

Yes. Chapter 8 gives you the full dismantle and assemble procedure for the hydraulic control unit, including the throttle pressure valve, valve block F2, and the valve blocks for clutches and brakes. You also get the oil level indicator removal and installation. It’s about 40 pages of content in this one section alone.

Will this manual help with the mechanical transmission section?

It will. Chapter 11 covers the mechanical transmission section—planetary carrier I and II dismantle and assemble for the HP 502/552/592 models. Sun gear end play measurement and tapered roller bearing adjustment are included.

You’ve read enough. If you’re tearing into an Ecomat 2, you need specs you can trust. Stop relying on forum threads and generic charts. Access the Factory Manual right now and keep it on your tablet in the bay. One stuck bolt torqued wrong can cost you an entire weekend. This manual pays for itself the first time you use it to get the right converter installation dimension.