Could be a couple of things:
Most likely: A bearing in the motor. They can be changed, but sometimes it is easier to just do the whole motor swap.
Less likely: Something stuck in the impellar that is creeping out and rubbing on the diverter - just take it apart and see (all 3 scenarios mean disassembling the pump so...)
Somewhat likely: That model has a diverter held on with SS screws, I have seen them rust out and the diverter get into the impellar. This is especially true on pools with a SWG.
Personally, I would let it go till you can't stand the noise, especially if you plan on just replacing the motor.
