A leaf spring for a centrifugal clutch of a transport refrigeration unit, and a centrifugal clutch incorporating the leaf spring are provided. The centrifugal clutch includes a drum, a hub, at least two friction pads, and at least one leaf spring between each respective friction pad. The leaf spring includes a frame and an indicator tab. The indicator tab of the leaf spring is configured to indicate when at least one friction pad of the centrifugal clutch is in need of replacement. This indication may be in the form of an audible sound generated when the indicator tab engages the internally facing surface of the drum. The indicator tab may be configured to only be able to engage the internally facing surface of the drum when the friction material of the friction pad has a thickness suggesting it is worn.