Whose else 6 speed is nosiey? Mine has got a rumble when in netraul with the clutch engaged, I can tell its the gears. If I pump the the clutch it goes away. I just had the bugger rebuilt and I am running the extra quart of fluid.

 

My NV5600 is getting pretty noisy, but it's just about due for a rebuild. Of course I can't really tell any more if it's the gears or the clutch rattling anymore...
Don't know what to say about your issue, except that I hope you don't have any major issues with it.

 

Mines noisy when i push in the clutch but I think thats the clutch. The only other thing i notice is the is kind of growls/whines when i load it down (like shifting into 6th at 30 mph )