Had the same problem with my steering. Toyota did the repair under warranty with less than 40,000 km on the clock, the knock disappeared, it was a knock that could be felt but not heard. The steering felt weird especially when turning left in sweeping bends. It felt like driving an old car car with a worn engine mounts, It felt like the engine was rocking backwards on acceleration and dropping forwards on deceleration. It was obviously not the engine mounts but the way the steering feel translated the loading up of the steering in the bend under acceleration.
