Okay, my memory was a bit fuzzy regarding the noise, so called my son.
It was similar in all gears and he describes as it as somewhat of a "rattling" type noise.
Since the shaft had moved forward, the rear spline for the pto was partially riding on the rear bearing. Spline was still okay, but perhaps enough spline spinning around on rear roller bearings to have caused the noise.... Hmmm???
We did not replace the front bearing. Noise was on level ground.
Additional info that may be helpful. The Cub would stall out when tried to run in 3d. (Before the split, I was thinking that rear bearing was "all messed up" and probably had shaft area messed up; thus binding and 3d gear just couldn't handle it. But that was not the case. Cub now runs fine in 3d as well.
Reason for my continued interest is noise in a couple of Cubs I have and possible causes, thus planning for parts before splitting - as well as what to look for when I open them up.
Oops, also, the front bearing oil hole was gummed up. We cleaned it and splash "collector". Counter-oops, the front bearing was a sealed bearing. Hmmm? Still pondering.