May 26, 2026 Service bulletin

KW: A Transmission Control Module (TCM) software update is now available for certain T680, T880, and W990...

Kenworth technical service bulletin 27-012 for 2025-2026 Kenworth T680, 2025-2026 Peterbilt 579 and 2025-2026 Kenworth T880 and others.

Bulletin number: 27-012
Component: Power train
Summary: KW: A Transmission Control Module (TCM) software update is now available for certain T680, T880, and W990 chassis with Eaton Endurant transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails. Please see the Eaton bulletin TAIB-1015 in the Attachments section for details. PB: A Transmission Control Module (TCM) software update is now available for certain Model 567, 579, and 589 chassis with Eaton Endurant transmissions, TCM software version R5.5 or later and an AT5 controller, where the TASPS fails. Please see the Eaton bulletin TAIB-1015 in the Attachments section for details.

Owners of these vehicles have filed 1 complaints in the transmission category.

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