In Allison AT, MT, and HT four-speed transmissions, the first clutch is applied only in which state?

In Allison AT, MT, and HT four-speed transmissions, the first clutch is applied only in which state?

• A. First Range
• B. Neutral
• C. Reverse
• D. Fourth Range

Answer: (B)

In these four-speed Allison transmissions, clutches control which gear sets are connected to the input and output to create the four forward speeds. The first clutch has a specialized role that only comes into play when the transmission is in neutral. Engaging this clutch in neutral helps align and prepare the gear train for the next drive range without transmitting torque to the wheels. In any forward range or in reverse, the system uses the other clutch(es) to establish the desired gear, so the first clutch stays disengaged. That’s why the first clutch is applied only in Neutral.

In these four-speed Allison transmissions, clutches control which gear sets are connected to the input and output to create the four forward speeds. The first clutch has a specialized role that only comes into play when the transmission is in neutral. Engaging this clutch in neutral helps align and prepare the gear train for the next drive range without transmitting torque to the wheels. In any forward range or in reverse, the system uses the other clutch(es) to establish the desired gear, so the first clutch stays disengaged. That’s why the first clutch is applied only in Neutral.