Allison upgrades fully automatic bus transmissions
By Luke Willetts - 30th January 2025
USA – Gearbox and e-axle manufacturer Allison Transmission Inc announced an “uprate”* to its B400 and B3400 xFE fully automatic transmissions, including retarder models. The B400 and B3400 xFE transmissions, used in buses, have been upgraded to support higher power and torque capacities. Specifically, they now accommodate up to 350 horsepower and 1,150 ft-lbs of torque.
Allison confirmed that the primary motivation behind this enhancement is to ensure compatibility with the upcoming Cummins X10 engine, which is being introduced to meet new EPA (Environmental Protection Agency) legislation**. By uprating these transmissions, Allison enables fleets operating buses to continue specifying the B400 and B3400 models as they transition to the new Cummins X10 engine for emissions compliance.
