VPI Classic motor question

I have a Classic with the 600 RPM motor. The table is 2.5 yrs old. The motor started making a swooshing sound on each rotation about a year ago which continued after lubricating it. The sound could only be heard with the ear to the pulley and the speed stability seemed fine with the SDS. I lubricated the motor again about two weeks ago, including removing the pulley and cleaning the shaft, and the swoosh continued. Today I started hearing a more frequent noise that sounds like a very low friction sound. Still very low, but what the hell?

Is there is anything I can do about it at this point? I don't think putting more oil into the motor after I just lubricated it will fix it. If the speed appears to be ok, should I just ignore it? The first time I heard the noise VPI did not offer any advice beyond lubricating the motor. Is replacing the motor the only way to take care of the problem perhaps?

Any advice and feedback would be appreciated.