71, It seems like you may be on to it there. Its a ball bearing and and all though many have a small amount of play, the in-out play in the direction of the shaft may be what you hear as the suspension pushes/pulls it in and out. Even at that, the inner CV joint shouldn't be transferring a bunch of end to end thrust.
If the inner race moves a whole 1/8" of inch, I can't imagine that bearing sounds real quiet. Can you confirm the shaft is not sliding in the inner race or are they fused together as many have shown us? That bearing has pretty easy life compared to say a wheel bearing and should last a long time, but if it has a 1/16" of an inch of radial free play I'd replace it.
Can you see where the seal went bad and let the grease out?
Edit: you folks with these rusted up cars underneath, I feel for you but am thankful mine looks nothing like that underneath!
If the inner race moves a whole 1/8" of inch, I can't imagine that bearing sounds real quiet. Can you confirm the shaft is not sliding in the inner race or are they fused together as many have shown us? That bearing has pretty easy life compared to say a wheel bearing and should last a long time, but if it has a 1/16" of an inch of radial free play I'd replace it.
Can you see where the seal went bad and let the grease out?
Edit: you folks with these rusted up cars underneath, I feel for you but am thankful mine looks nothing like that underneath!