Description

JLG 600A, 660AJ 2015 Service Manual – Factory Specs for Maintenance and Repair

If you’re turning wrenches on a JLG 600A or 660AJ boom lift and you’re not using the factory service manual, you’re working blind. I’ve seen too many guys torque swing bearing bolts by feel, or drain hydraulic oil without knowing the right spec for the 660AJ. That’s how platforms drift and bolts snap. This is the real book – 348 pages, published February 3, 2015, straight from JLG. It covers serial number 0300177361 to present, with a note on page 2 that it also applies to serial number 0300176207. No aftermarket nonsense. The JLG 600A, 660AJ 2015 Service Manual lays out every spec, every safety precaution, and every step in the order it should be done. Stop guessing and get the OEM source.

348 Pages of Factory Specs for the 600A and 660AJ

You get the full Table of Contents: Section A covers maintenance safety precautions – read that before you touch any hydraulic line. Section 1 has operating specs, dimensional data, capacities, tire pressure, engine data, function speeds, torque requirements (Section 1.7), hydraulic oil specs, and major component weights. Section 2 walks through machine preparation, inspection intervals (pre-start, pre-delivery, annual), and service guidelines that cover bolt usage and torque application, bearings, gaskets, hydraulic lines, and cylinder drift tests. Section 3 dives into chassis and turntable: tires, torque hub, free wheeling, drive motor, oscillating axle, steer adjustments, swing drive, swing bearing with torque values, swing brake, rotary coupling, generator, and four different engine sections – Deutz D2.9 L4, Deutz D2011, GM, and a dedicated section on glow plugs and spark arresters. That’s a lot of coverage for one book.

Engine Coverage: Deutz and GM Sections

If you’re chasing an engine problem on a 600A or 660AJ, this manual has the specifics. Section 3.12 covers the Deutz D2.9 L4 – oil changes, filter changes, fuel filter replacement. Section 3.13 covers the Deutz D2011 – same deal, plus fuel strainer cleaning. Section 3.18 goes into the GM engine with drive belt maintenance, electrical system, oil level checks, coolant fill for dual fuel, and more. There’s also a section on Deutz EMR 2 and bio fuel handling. The manual spells out the exact procedure for changing oil filters and the torque for drain plugs. No generic instructions – these are JLG-approved steps.

Torque Values: Where to Find Them in the Manual

Torque is not a suggestion in this trade. Section 1.7 gives you the torque requirements table – that’s your go-to for standard fasteners. But the manual goes further: Section 3.2 on the torque hub includes tightening and torquing bolts for the hub assembly. Section 3.8 on the swing bearing has dedicated torque values for the turntable mounting bolts. Section 3.9 on the swing brake (Mico) also includes torque specs for reassembly. And Section 2.2 explains bolt usage and torque application – how to tighten in sequence, why you use a calibrated wrench, and what happens if you skip a step. Don’t be the guy who strips a hub bolt because he trusted a Chilton for a JLG lift.

Hydraulic System Safety – Read This Before Starting

Section A makes it clear: the hydraulic system operates at extremely high pressures. Page 3 states, “every effort should be made to relieve any system pressure prior to disconnecting or removing any portion of the system.” I’ve seen a guy lose two fingers because he cracked a fitting under pressure. This manual also covers cylinder drift testing (Section 2.4), hydraulic oil changing (Section 2.3), and the oscillating axle bleeding procedure (Section 3.5). Follow these procedures, and you keep the machine safe and yourself alive.

Bolt Usage and Torque Application – Section 2.2

Section 2.2 isn’t just a paragraph; it’s a set of rules. It covers pressure-fit parts, bearing installation, gasket replacement, and torque application. It also includes specific guidance for hydraulic lines and electrical wiring – don’t mix up those two. If you’re rebuilding the torque hub on a 660AJ, you need to know the correct sequence for the input carrier sub-assembly bolts. The manual has it. For the swing drive (Section 3.7), the gear backlash adjustment is critical, and the torque values for the motor control valve are right there. Everything you need to avoid a call-back is in this book.

Related Manuals You Might Need

If you’re doing a full teardown, you might also want the JLG 600A 600AJ 2013 Parts Catalog for part numbers. For daily operation and pre-start checks, the JLG 600A, 600AJ 2015 Operators Manual – Factory OEM Specs covers the operator side. And if you work on the RS10 model, grab the JLG RS10 2013 Service Manual – Factory Specs & Diagnostics. Outside JLG equipment, if you ever need to understand the basics of a manual transmission for another project, check out Manual Transmission or Manual Transmission for general theory.

Who Should Use This Manual?

This is for service technicians, shop owners, and advanced DIYers who have a JLG 600A or 660AJ in their yard. If you’re a beginner, you’ll still get value, but you need to respect all the safety warnings – especially around hydraulics and elevated booms. The manual is written for someone who can read a torque table and use a micrometer. If that’s you, this is the only service manual you need. If you’re a shop owner, put a copy in every bay. It’ll save you from buying parts twice because someone tightened a swing bearing to 150 ft-lbs instead of the factory spec.

Source Authenticity: OEM, Not Aftermarket

This is a JLG factory service manual, part number 3121616, dated 2015. It’s not a reprint from a third-party that misspells “torque” and omits the safety section. The OCR shows the exact wording from JLG – including the bold warnings about modification, the statement that no smoking is mandatory during refueling, and the instruction to remove all rings and watches. You get the same document that JLG sends to their dealers. Trust the source that built the machine.

Does this manual cover both the 600A and 660AJ models?

Yes. Both models are included in a single manual. Page 2 confirms coverage for serial numbers from 0300177361 onward, and also notes applicability to serial number 0300176207.

What engine types are included?

It covers Deutz D2.9 L4, Deutz D2011, and GM engines. Sections 3.12, 3.13, and 3.18 have specific procedures for oil changes, filter replacement, and coolant fills. Also includes spark arrester cleaning and glow plug info.

Are torque values listed for every bolt?

The manual dedicates Section 1.7 to torque requirements with a table covering fastener grades, lubrication, and thread engagement. For specific assemblies like the torque hub (Section 3.2), swing drive (Section 3.7), and swing bearing (Section 3.8), separate torque values are provided during reassembly steps. Section 2.2 explains bolt usage and torque application best practices, including tightening patterns and the importance of using a calibrated torque wrench. Skipping these specs is how you strip threads in the field and lose time.

Can I use this for troubleshooting electrical issues?

Yes. It includes wiring diagrams for engine control systems like Deutz EMR 2 and the GM electrical system, as well as diagnostics for the battery and generator sections (3.11).

Look, I’ve been doing this for 28 years. Every time I see a machine come in with stripped threads or a hydraulic leak from a wrong seal, it’s because someone used a generic manual. The $60 you spent on a PDF from a pop-up site isn’t worth the hospital bill. The JLG 600A, 660AJ 2015 Service Manual from AutoRepairManuals is the OEM document, full factory specs, no missing pages. If you want to repair it right and only once, access the factory manual.