Allison Bus Series

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Allison Bus Series
Cutaway of Allison 4000-series transmission (marketed as B500)
Classification	Automatic transmission
Application	transit and highway buses

The Allison Bus Series are medium and heavy duty automatic transmissions for transit buses and highway motorcoaches designed and manufactured by Allison Transmission. Each of the six models in the Bus Series is available in 5 or 6 speeds with an integral hydraulic retarder as an option.