99 ZF 650 noise

[mcgoo422000]

I have 99 SD with ZF 650 trans. done been gone into 4 times.
I am under a load was in greenwood cruising 2 65 and all of a sudden
the trans. starts sounding like a pea sheller. I stop and checked it.
Full of fluid and it's clearand no leaks.
I drive and it's making noise in all gears except 5th.
I have drive on into dallas in fifth gear. I am thinking maybe a tooth come
off a gear?? Any ideas out there?