Mack service campaign S4558 202506
Mack filed this with NHTSA as a service campaign dated Jun 18, 2025, received Jul 3, 2025, about the power train. It names 4 model years (2021–2024). 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 communicationMack trucks has determined that certain model year 2021-2024 PI models built with 4.19 rear axle ratios could experience elevated axle oil temps under high road speeds. To correct this issue the 4.19 ratio carriers need to be swapped to 3.79 ratio carriers. Follow the instructions below to replace both carriers with new ones.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| S4558 202506 | Service campaign | Jun 18, 2025 | 11020159 | 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: 2021 Mack Pinnacle (pi/pn); 2022 Mack Pinnacle (pi/pn); 2023 Mack Pinnacle (pi/pn); 2024 Mack Pinnacle (pi/pn).
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 S4558 202506 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 S4558 202506 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 S4558 202506 cover?
The manufacturer filed it against 4 model years: 2021 Mack Pinnacle (pi/pn), 2022 Mack Pinnacle (pi/pn), 2023 Mack Pinnacle (pi/pn), 2024 Mack Pinnacle (pi/pn). Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.