I bought a craftsman 4" trim circular saw ( circa 1975 ) at an estate sale while back and it seems to make some rattling noise when powering up or down, but not at operating speed. The saw had very little use and run nicely otherwise. Just wondering if the gear box grease could be replaced with synthetic grease and what viscosity to use. Saw is model 315.11890. Also anybody know a source for the manual for the saw. thanks
