Knocking that matches wheel speed

[Dubclutcher]

Hi all, 5 speed 14 wrx hatch here. Recently got a new exedy stage 1 clutch put in by a local shop. Every time I come to a slow or a stop there is a squeaky knock that decelerates as the car decelerates. I doubt it’s the clutch. Transmission fluid is low so I’ll be doing a change tomorrow. In the meantime, is this knocking a symptom of a serious tranny issue?

Edit: this is only audible during low speeds (5-10 mph)