2005 with G56, got an annoying "hissing" noise coming from tranny when its in neutral, 1st, 3rd and 5th. No noise in 4th or 6th. Noise is not crazy loud but noticeable. About 28000 km, driven decent. Took it into dealer because it became noticeable over the last four months and they called it normal gear noise. Tranny shifts fine, just worried that something may be on its way out. Don't want it piling up on me climbing a hill with my travel trailer.