I have, among others, a Series V Snipe,fittted with the Borg Warner DG auto transmission which I'm seeking some input on, please.
It has an audible, low pitch vibration from the driveline; I believe the transmission or tailshaft which comes in around 35 mph, and is gone again by 45.
This is not load dependant, just speed. It persists even if you slip the vehicle into neautral. The vehicle drives beautifuly otherwise, and the noise did disappear randomly for several hundred miles; I believed because the tranny fluid had been topped up.