Well I've been thinking and testing it a bit more. it definitely doesn't happen if you keep the revs up. With motorbikes you would feel it as snatch in the primary chain. On ours beasts I reckon the bevel drive is the likely candidate. All gear trains have backlash to some degree or another or they lock solid. just rock any geared system and you'll feel it. I'm guessing the drivetrain components are running faster than the engine as they may do post overrun when you dip,the clutch and let the engine revs drop, those same components will be taking up the full slack(or backlash) in the various gear trains in this condition. Release the clutch on a slow engine and your removing that load momentarily causing the gear trains to reverse lash if that makes any sense. I reckon there may be more backlash coming off load on most gear trains and that why we feel it more on slow overrun than on acceleration. I think I may be overthinking this!!!!
