Rattling noise from HURTH transmission

[jmm48m60]

Have this noise coming from starboard trans. stops when you increase idle or place it in gear. Any thought?

[bud37]

Just a little more info cause guys will ask......has this just started, how is the tune on that engine, low idle or rough all of a sudden, starts ok ???

[SanJuanDreamer]

I had a sound that was like stones in a cement mixer.
Like you mention, it stopped after increasing RPMs.
Had the trans rebuilt by Harbor Marine.
Their conclusion was the clutches were somewhat burnt and there was some damage to a couple gears, but...they also said I still had plenty of time on it and didn't need the rebuilt at that time.
Its an embarrasing sound but...my opinon...Id wait until something odd happens...whats odd? I dont know becasue I had it rebulit.
Something odd to me is if it dosent go into gear as fast as it used too or something small which catches your attention.

My two cents...I may deserve change.

[Viper]

The most common reason is low idle though as mentioned a poor running engine will cause it too as will internal issues. What rpm is she idling at? Is there any shaft creep in neutral? Did you check the fluid level and its condition?