OK so it does now sound like a pump issue, could something have gotten into the impeller? I have had to fetch out all manner of stuff from impellers and that would at least not require a full strip down, just removal of the front cover if you can't get your fingers down inside to fish anything out. (totally unplug the pump first).
Failing that it could well be the bearings, if you are not up to the job it's worth finding a shop who can, bearings are low cost and reasonably easy to change providing the bearing hosing isn't damaged through running excessively hot.
Good luck and let us know how you get on.