how bad is the grinding? is it on power or off power that you notice it?

does it do it at idle?

have you removed the tranny?

i noticed the same thing with mine but it never became a problem i checked everything,when i put my f.o.c. in i saw that the small screw holding one of the gears on the bevel gear had backed out and dropped in the case.
luckily it dropped into a big blob of grease and never tore anything up