# Service bulletin TSIB 26\-05

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.

- Type: Service bulletin
- NHTSA id: 11034101
- Published by NHTSA: 2026\-06\-26
- Manufacturer's number: TSIB 26\-05
- Manufacturer's date: 2026\-06\-11
- NHTSA component: ENGINE

## NHTSA's summary

This bulletin introduces an optional product improvement to the A/C compressor drive system for coaches equipped with a Cummins X12. The improved pulley system is available for customers who wish to reduce noise and vibration characteristics and may be installed at the customer’s discretion.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11034101-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11034101-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Vehicles listed

- 2018 to 2022 MCI D4000
- 2018 to 2023 MCI D4000ISTV
- 2018 to 2021 MCI D4005
- 2026 MCI D4020
- 2024 to 2026 MCI D4020ISTV
- 2018 to 2024 MCI D4500
- 2018 to 2024 MCI D4505
- 2020 to 2026 MCI D4520
- 2024 to 2026 MCI D45CRT
- 2018 to 2025 MCI D45CRTLE
- 2018 to 2026 MCI J4500

JSON: [/v1/bulletins/11034101](/v1/bulletins/11034101)

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