help with shimano sustain 2500fg

so i have used my shimano sustain 2500 fg for 2 seasons now and love the reel. it has always been very strong and smooth and puts up with lots of fishing. i caught 10-20lb carp, 10lb striper, many bass, and even a 15lb cownose ray with it. i was fishing last week at a saltwater spot and when i got home i rinsed it like i always do. now i feel slight resistance and grinding with it. i pulled it apart to regrease and clean it up which helped a little, but it isnt the quiet smooth reel i have adored. i feel resistance at specific points when winding it slowly.
anyone have any experience here? is it the ball bearings or is it another part that needs replacing? the bearings are sealed but maybe they need to be reopened and greased(just not sure how). i also hear a squeek when i wind the reel but cant imagine what it could be coming from since i regreased and oiled the reel so carefully.
all help is appreciated, i would prefer not to send it back to shimano for repair.