I managed to fix it 2 days ago, though it was not pretty.
I took the spider gasket out (it's slightly worn on some part), thoroughly cleaned it and the plate that it's sitting on. Then put some Permatex #2 (soft sealant that won't harden) and put that on the grooves of the plate that the spider gaskets sits on and put everything back on, it hasn't leaked at all for 2 days already with the pump running
Mind you, those #2 sealant is messy, you'll need gloves, mask and lots of paper towel, but it's fixed.
Thanks to the idea I got from this forum and others.