3121245 GM Engine Parts Supplement - Revision Log - Table of Contents

Oct 29, 2026

Illustrated GM engine parts supplement P/N 3121245 providing a revision log and a structured table of contents for engine component breakdown. Includes usage chart guidance describing Universal Ground Module (UGM) identification near ground controls/ground control box and notes for models, machine serial-number ranges, and Arctic Package availability. Organizes coverage across multiple engine variants (including .97L and 3.0L), with sections for short block, cylinder head, long block & dress components, electrical, pumps, intake/exhaust, fuel supply tiers, and special options.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages100

Reading Time4 h 12 min

AccessFree to download

SECTION 1 - USAGE CHART

SECTION 2 - .97L ENGINE

2-1 SHORT BLOCK COMPONENTS

2-2 CYLINDER HEAD COMPONENTS

2-3 LONG BLOCK & DRESS COMPONENTS

2-4 ELECTRICAL COMPONENTS

2-5 ALTERNATOR, WATER PUMP & PULLEYS COMPONENTS

2-6 STARTER COMPONENTS

2-7 FLYWHEEL HOUSING/PUMP COUPLING COMPONENTS

2-8 THERMOSTAT & INTAKE MANIFOLD COMPONENTS

2-9 FUEL SUPPLY COMPONENTS

2-10 EXHAUST COMPONENTS

SECTION 3 - 3.0L ENGINE

3-1 SHORT BLOCK COMPONENTS

3-2 CYLINDER HEAD COMPONENTS

3-3 LONG BLOCK & DRESS KIT

3-4 ELECTRICAL COMPONENTS

3-5 ALTERNATOR & PULLEY COMPONENTS

3-6 STARTER KIT

3-7 FLYWHEEL HOUSING/PUMP COUPLING COMPONENTS

3-8 AIR INTAKE COMPONENTS (SCISSORS LIFTS ONLY)

3-9 FUEL SUPPLY COMPONENTS-TIER 1 ENGINES

3-10 FUEL SUPPLY COMPONENTS-TIER 2 ENGINES

3-11 FUEL SUPPLY COMPONENTS-TIER 3 & 4 INTERIM ENGINES

3-12 MIXER ASSEMBLY (TIER 1 & 2 ENGINES)

3-13 INTAKE/EXHAUST MANIFOLD COMPONENTS

3-14 MUFFLER COMPONENTS-BOOM LIFTS

3-15 MUFFLER COMPONENTS-SCISSOR LIFTS

3-16 COOLANT SYSTEM COMPONENTS

3-17 ENGINE MOUNTING COMPONENTS

SECTION 4 - SPECIAL OPTIONS

SECTION 5 - PARTS NUMBER INDEX

Illustrated Parts Manual GM Engine Parts Supplement P/N 3121245 December 30, 2013 REVISION LOG NOTES: GROUND MODULE MODULE IDENTIFICATION NOTE: MODULE IS LOCATED NEAR THE GROUND CONTROLS OR IN GROUND CONTROL BOX . MODULE ON MACHINES“WITHOUT UGM”(UNIVERSAL GROUND MODULE) MODULE ON MACHINES“WITH UGM”(UNIVERSAL GROUND MODULE) March 15, 2008-Original Issue Of Manual May 1, 2011-Revised Manual July 25, 2011-Revised Manual October 21, 2011-Revised Manual February 15, 2012-Revised Manual August 2, 2012-Revised Manual January 23, 2013-Revised Manual June 30, 2013-Revised Manual December 30, 2013-Revised Manual 3121245 GM Engine Parts Supplement A REVISION LOG B GM Engine Parts Supplement 3121245 TABLE OF CONTENTS FIGURE NO. TITLE PAGE NO. SECTION 1-USAGE CHART ...............................................1-1 SECTION 2- .97L ENGINE .................................................2-1 2-1 SHORT BLOCK COMPONENTS .......................................... 2-2 2-2 CYLINDER HEAD COMPONENTS ........................................ 2-6 2-3 LONG BLOCK & DRESS COMPONENTS ................................... 2-10 2-4 ELECTRICAL COMPONENTS ............................................ 2-12 2-5 ALTERNATOR, WATER PUMP & PULLEYS COMPONENTS ................... 2-14 2-6 STARTER COMPONENTS............................................... 2-16 2-7 FLYWHEEL HOUSING/PUMP COUPLING COMPONENTS ..................... 2-18 2-8 THERMOSTAT & INTAKE MANIFOLD COMPONENTS ........................ 2-20 2-9 FUEL SUPPLY COMPONENTS ........................................... 2-22 2-10 EXHAUST COMPONENTS .............................................. 2-26 SECTION 3-3.0L ENGINE .................................................3-1 3-1 SHORT BLOCK COMPONENTS .......................................... 3-2 3-2 CYLINDER HEAD COMPONENTS ........................................ 3-8 3-3 LONG BLOCK & DRESS KIT ............................................. 3-12 3-4 ELECTRICAL COMPONENTS ............................................ 3-16 3-5 ALTERNATOR & PULLEY COMPONENTS ................................. 3-20 3-6 STARTER KIT ......................................................... 3-22 3-7 FLYWHEEL HOUSING/PUMP COUPLING COMPONENTS ..................... 3-24 3-8 AIR INTAKE COMPONENTS (SCISSORS LIFTS ONLY) ........................ 3-26 3-9 FUEL SUPPLY COMPONENTS-TIER 1 ENGINES ........................... 3-28 3-10 FUEL SUPPLY COMPONENTS-TIER 2 ENGINES ........................... 3-32 3-11 FUEL SUPPLY COMPONENTS-TIER 3 & 4 INTERIM ENGINES ................ 3-36 3-12 MIXER ASSEMBLY (TIER 1 & 2 ENGINES) .................................. 3-40 3-13 INTAKE/EXHAUST MANIFOLD COMPONENTS .............................. 3-42 3-14 MUFFLER COMPONENTS-BOOM LIFTS .................................. 3-44 3-15 MUFFLER COMPONENTS-SCISSOR LIFTS................................ 3-48 3-16 COOLANT SYSTEM COMPONENTS ...................................... 3-52 3-17 ENGINE MOUNTING COMPONENTS .................................... 3-54 SECTION 4-SPECIAL OPTIONS ............................................4-1 SECTION 5-PARTS NUMBER INDEX ........................................5-1 3121245 GM Engine Parts Supplement i TABLE OF CONTENTS FIGURE NO. TITLE PAGE NO. ii GM Engine Parts Supplement 3121245 SECTION 1 USAGE CHART USAGE CHART | Part Number | Description | Qty | | --- | --- | --- | | | MODEL & ENGINE USAGE:
Note: UGM refers to Universal Ground Module located near machine Ground Controls. See Revision Log for identification. | Ref
Ref | | | JLG Boom Lift Models: | Ref | | 1001117892 | 340AJ (See Section 2 for Breakdown)
Tier 3 .97L Complete Engine | Ref
Ref | | 2000354 | 400S/460SJ (See Section 3 for Breakdown)
Tier 1 3.0L Complete Engine (Machines Prior to SN 0300109274 without UGM) | Ref
Ref | | 1001091583 | Tier 2 3.0L Complete Engine (Machines SN 0300109274 to Present without U

FAQs

What is included in the GM Engine Parts Supplement 3121245?

It provides a revision log plus a table of contents covering an usage chart and detailed engine component breakdown for different engine variants and configurations.

How does the document define and locate the UGM (Universal Ground Module)?

UGM is identified as located near the machine ground controls or in the ground control box, with a note pointing readers to the revision log for identification details.

How does the usage chart help select the correct engine breakdown?

It maps JLG boom lift models and engine tiers to specific engine variants, using model notes and machine serial-number ranges, including cases with and without UGM and the Arctic Package availability note.

Oct 29, 2026

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