Mack service campaign S4757 022026
Mack filed this with NHTSA as a service campaign dated Feb 1, 2026, received Mar 3, 2026, about the engine. It names 3 model years (2025–2026). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationSC - Certain model AN(4)’s and PR’s could experience DEF leaks or crystallization due to the installation of incorrect fasteners for the Urea Dosage Valve.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| S4757 022026 | Service campaign | Feb 1, 2026 | 11029456 | not yet checked |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themAlso filed against: 2026 Mack Anthem AN (4); 2025 Mack Pioneer PR (4); 2026 Mack Pioneer PR (4).
None of these model years has a page on this site (it covers EPA-certified cars, trucks and SUVs from 2016), so the bulletin is listed here on its own.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mack S4757 022026 a recall?
No. A service campaign is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls.
Is the S4757 022026 repair free?
A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does S4757 022026 cover?
The manufacturer filed it against 3 model years: 2026 Mack Anthem AN (4), 2025 Mack Pioneer PR (4), 2026 Mack Pioneer PR (4). Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.