Thanks. Hmm. Engine is Universal 5432 (32 hp) with HBW150V (Hurth V drive transmission). Noise occurrs in neutral, low rpm
. Increases in loudness, not frequency, as engine warms up. In gear
, forward or reverse, noise goes away as rpm increases.
Per one mechanic
, who listened to sound in neutral, forward & reverse, could be the throw-out bearing (also called an operating cone). He's researching and we're researching.