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7M3978 — EXPANDER,PISTON RING

✓ Government record, cited
— · COMPONENT
PRODUCT OVERVIEW

7M3978: EXPANDER,PISTON RING.

The EXPANDER,PISTON RING is a the manufacturer industrial component. Key specifications include end_item_identification: CATERPILLAR ENGINES, ring_diameter_accommodated: 5.406 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5120-01-184-7174, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
7M3978
NSN: 5120-01-184-7174
FSC: 5120 — Hand Tools, Nonedged, Nonpowered
CAGE: 11083 — CATERPILLAR INC DIV CATERPILLAR DEFENSE (USA)
SPECIFICATIONS
end_item_identificationCATERPILLAR ENGINES
ring_diameter_accommodated5.406 INCHES NOMINAL IN
NSN5120-01-184-7174
COMPONENT DIAGRAM
COMPONENT MAIN IC EDGE CONNECTOR No detailed specs available EXPANDER,PISTON RING TITLE COMPONENT PN 7M3978 MFR EXPANDER,PISTON RING
KEY FEATURES
•
RING DIAMETER ACCOMMODATED: 5.406 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
RING DIAMETER ACCOMMODATED5.406 INCHES NOMINAL IN
END ITEM IDENTIFICATIONCATERPILLAR ENGINES
OTHER ITEMS IN FSC 5120 — Hand Tools, Nonedged, Nonpowered
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5120-00-001-2642 5120-00-001-2644 5120-00-001-2650 5120-00-001-2651 5120-00-001-2652 5120-00-001-2653 5120-00-001-2654 5120-00-001-2655
SUBSTITUTES & CROSS-REFERENCES 1
28KP839Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 7M3978?
7M3978 is a EXPANDER,PISTON RING.
What parts can replace 7M3978?
There is 1 known substitute for 7M3978: 28KP839. Substitute compatibility should be verified for your specific system.
What is the NSN for 7M3978?
7M3978 is cataloged in the U.S. Government catalog under NSN 5120-01-184-7174. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.