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Service campaign S4325 072025

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService campaign
NHTSA id11021335
Published by NHTSA2025-08-04
Manufacturer's numberS4325 072025
Manufacturer's date2025-07-08
NHTSA componentENGINE

NHTSA's summary

CBR - Mack Trucks has identified that certain 2025 model year Mack Medium Duty (MMD) vehicles may have been assembled with insufficient torque on the fan hub retaining hardware.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Vehicles listed
MACK MD2025

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
CBR 2107-21 2025052025-06-02. Service bulletin. Mack DEF Level (UQLS) Sensor Troubleshooting Guide - US17+OBD16 Emissions and Newer
CBR-561 2025032025-04-02. Service bulletin. If oil dilution is suspected refer to the applicable CBR solution below: ∙ CBR-659􀁡Mack Chassis - Oil Diluted With Fuel; Fuel In Oil, Diagnostic Information - All Emissions, All Model Years
S4325 2024122025-01-02. Service campaign. Mack Trucks has identified that certain 2025 model year Mack Medium Duty (MMD) vehicles may have been assembled with insufficient torque on the fan hub retaining hardware. To address this issue and maintain Mack's high-quality standards, please follow the instructions below to properly retorque the fan hub retaining hardware.
CBR-997 2024112024-12-02. Service bulletin. Vehicles may present with oil leak coming from the clutch/flywheel housing and observation of burned clutch smell or clutch slipping. These symptoms can be mistaken as a crankshaft rear main seal leak, when the actual cause is the crankshaft adaptor O-ring.
CBR-2013 2024042024-05-01. Service bulletin. CBR: Turbo Compound (TC) Hot Side Noise, Diagnostic Information.
CBR-2139 2024032024-04-02. Service bulletin. CBR: Vehicles built with an 11 liter engine may experience a complaint of excessive fuel in the oil. It is possible that the source of the fuel is the rear fuel galley plug in the cylinder head.