# Service bulletin TSIB 26\-02

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: 11028623
- Published by NHTSA: 2026\-02\-06
- Manufacturer's number: TSIB 26\-02
- Manufacturer's date: 2026\-01\-20
- NHTSA component: ENGINE; POWER TRAIN

## NHTSA's summary

Bulletin describing the proper de\-aeration for Allison EGEN Flex Hybrid coolant loops.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11028623-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11028623-9999.pdf)

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

## Components

Engine, Transmission and driveline

## Vehicles listed

- 2022 to 2026 NEW FLYER XDE35
- 2022 to 2026 NEW FLYER XDE40

JSON: [/v1/bulletins/11028623](/v1/bulletins/11028623)

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