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Service campaign S4533 202608

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 id11036596
Published by NHTSA2026-09-02
Manufacturer's numberS4533 202608
Manufacturer's date2026-08-05
NHTSA componentENGINE
Manufacturer's systemEngine: Turbo

NHTSA's summary

Mack Trucks has determined that certain AN model trucks equipped with an MP8 Turbo Compound (TC) engine may experience TC Double Idler Gear failure due to incorrect bearing preload. TC units within this population are suspected to be affected, which could result in failure and potential engine damage. For the affected vehicle population, please follow the instructions provided below to remove the TC unit, replace the double idler gear with a new one, and reinstall the TC unit.

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 ANTHEM (AN)2025 (the catalog's model; the bulletin names a series or trim of it)

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

Recalls for the same vehicles and component
25V2560002025-04-17. ENGINE AND ENGINE COOLING:ENGINE:DIESEL

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
TSB M-913-001 2026092026-10-02. Service bulletin. Parker engine-mounted hydraulic pump service bulletin.
CBR-2592-1 2026062026-06-29. Service bulletin. The purpose of this CBR is to provide steps on how to correct a customer complaint of DTC P107B86 accompanied With intermittent loss of throttle.
CBR 199 2025122026-01-05. Service bulletin. Vehicles affected by this issue will show coolant runoff on the front rights side of the engine.
CBR 2171-11 2025112025-12-03. Service bulletin. CBR - Mack Temperature Sensor Troubleshooting Guide
CBR 199-6 2025112025-12-03. Service bulletin. CBR - 13 Liter Engines ONLY - Engine Coolant Pump Housing Leak; Coolant Found Around The Oil Cooler Duct Cover Or In Between The Coolant Pump Housing And Oil Cooler Housing.
S4533 0720252025-08-04. Service campaign. SC - Mack Trucks has determined that certain AN model trucks equipped with an MP8 Turbo Compound (TC) engine may experience TC Double Idler Gear failure due to incorrect bearing preload.
CBR 2107-21 2025052025-06-02. Service bulletin. Mack DEF Level (UQLS) Sensor Troubleshooting Guide - US17+OBD16 Emissions and Newer
CBR 170-8 2025052025-06-02. Service bulletin. Inactive Code P25AE00 Being Generated After A Hard Pull And A Momentary Drop In Engine Oil Pressure (Low Oil Pressure) (Possible Related Codes - SPN4811 , SPN 100 , PID 100)
CBR-2449 2025032025-04-02. Service bulletin. Cummins Exhaust Aftertreatment System (EATS) catalysts may experience cracking, which may be attributed to excessive vertical vibration in the exhaust stack. To mitigate this issue, a modification to the exhaust stack length is required.
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