Abstract: Apparatus and methods for locking a discharge chute of a mixing vehicle are disclosed. The locking apparatus can be mounted to existing discharge chutes and frame arrangements and may utilize existing pneumatic systems of the mixing vehicle. The locking apparatus generally include a base having a first arm and a second arm pivotally secured to the base. An airbag may be positioned between the first arm and the second arm to bias a clamping region of the locking apparatus in a locked or a released state depending on the configuration of the locking apparatus.