Same for me! New drive unit is silent and still loving the Heckler SL.Replacement DU was refreshing to the ears. I’ve got 15 sloppy PNW rides (160 mi, 30k feet) on the new one with no issues so far, and I’m listening closely
My original DU was produced May 2023, hardware version 2. New one produced September 2023, version 5, so seems like some rolling improvements are underway.