From my Cub Cadet ZTR (34hrs), removed 1 qt per side of 20W-50 oil and sent it out for UOA. Looks a sodium based additive package, with API SN levels of Zinc and Phosphorous. Calcium was a mediocre 1400ppm and no Magnesium. Silicon was 40 ppm and similar to my Toyota's ATF UOA. Probably silicone RTV gasket material. Surprisingly there was 33 ppm of Pb. I called HydroGear and they were not sure where it came from. They suggested powder metal gears. I also called Fabick Cat to redo the oil analysis and the results was again 33ppm Pb. Any idea where it is from?