I take it you forgot the "not" as in that does not sound good. Im full of fluid; but, the sound is not"rattling" it's more of a fluttering. I had an old K car which had a sideways engine, and it had a single bolt that aligned one portion of the engine/tranny. That bolt broke from extreem dips in the country, and the trans made a similar clatter ,even though it ran. I think the tranny of my GMC Vandura is not shot, as you suggest; I think there is another problem /fix. But thankx anywayz. Im a fix it guy, not a trow it out guy