Sorry for not getting back to this sooner. I get to the forum when I can. I doubt it is the bearings because you shouldn't have done anything to disturb them. But, sometimes with bearings that old it doesn't take much to cause a problem. That SPX-1610 is probably the motor part number. Mine is an SP-1607. Something to try is to unload the motor and see if the noise persists or changes. Empty the pump basket and turn it on with no water. Won't hurt to run it this way for a short time. I'm wondering if there could be physical contact in the impeller area. Clearances are close. Bearing noise is usually a squeal or grinding noise. I just found out how to post pics so here is a shot of the rear of mine. Yours is probably similar.
Al