The Muffler,exhaust, cataloged under National Stock Number 2990-00-423-9109, is classified within Federal Supply Class 2990 (Miscellaneous Engine Accessories, Nonaircraft) of the Engine Accessories group. The manufacturer of record is Caterpillar Inc Div Caterpillar Defense. Government technical data includes 20 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 2990-00-423-9109 |
| Primary Part Number | 3B6238 |
| Item Name | Muffler,exhaust |
| FSC / FSG | 2990 / 29 — Miscellaneous Engine Accessories, Nonaircraft |
| Manufacturer | Caterpillar Inc Div Caterpillar Defense |
| Status | ACTIVE |
| Operating Position | VERTICAL |
| FSC Application Data | EXHAUST GROUP,DIESEL ENGINE |
| Inlet Outside Diameter | 2.656 INCHES MINIMUM AND 2.688 INCHES MAXIMUM SINGLE INLET IN |
| Inlet Location | CENTRALLY IN END SECTION OF BODY |
| Coolant Type | AIR |
| Design Type | DRY |
| Overall Diameter | 8.500 INCHES NOMINAL IN |
| Outlet Inside Diameter | 2.516 INCHES MINIMUM AND 2.531 INCHES MAXIMUM FIRST OUTLET IN |
| Inlet Projection Length | 1.875 INCHES NOMINAL SINGLE INLET IN |
| Muffler Design | STRAIGHT THROUGH |
| Outlet Outside Diameter | 2.641 INCHES MINIMUM AND 2.656 INCHES MAXIMUM FIRST OUTLET IN |
| Tube Quantity | 1 |
| Inlet Connection Type | UNTHREADED SINGLE INLET |
| Body Shape | ROUND |
| Surface Treatment | ALUMINUM |
| Inlet Inside Diameter | 2.531 INCHES MINIMUM AND 2.562 INCHES MAXIMUM SINGLE INLET IN |
| Material | STEEL LOCATION NOT OTHERWISE SPECIFIED |
| Outlet Projection Length | 19.938 INCHES MINIMUM AND 20.062 INCHES MAXIMUM FIRST OUTLET IN |
| Outlet Connection Type | UNTHREADED FIRST OUTLET |
| Outlet Location | CENTRALLY IN END SECTION OF BODY |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 3B6238 PRIMARY | Caterpillar Inc Div Caterpillar Defense (USA) |
NSN 2990-00-423-9109 is a Muffler,exhaust, manufactured by Caterpillar Inc Div Caterpillar Defense, classified under FSC 2990, Miscellaneous Engine Accessories, Nonaircraft. Status: active.
NSN 2990-00-423-9109 has 1 manufacturer part number on file: 3B6238 (Caterpillar Inc Div Caterpillar Defense).
Key specifications for 3B6238: Operating Position: VERTICAL; FSC Application Data: EXHAUST GROUP,DIESEL ENGINE; Inlet Outside Diameter: 2.656 INCHES MINIMUM AND 2.688 INCHES MAXIMUM SINGLE INLET IN; Inlet Location: CENTRALLY IN END SECTION OF BODY. 20 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.