ASTM-d130 is a test for evaluation of lubricant additives tendancy to corrode yellow metals. Yellow metal corrosion has become a more critical factor as the EP additives in gear oils have become more concentrated. Older gearboxes with yellow parts (brass, bronze, copper) synchros, and other parts will be damaged by high additive content in some new oils. The ASTM-d130 test rates oils by imersing a prepared copper strip in the lubricant at 2 temperatures in the range typical of the gearbox in service (212 degrees, and 250 degrees F). The ratings go from a "1a" with slight discoloration, but barely noticeable, to a "4c" which is severely corroded, blackened, and pitted. Use care with older gearboxes and highly corrosive oils.
In standardized test method ASTM D130 for oils or D4048 for grease, the rating of 1A is given for appearance of freshly polished copper coupons, and 1B indicates slight tarnish. The ratings proceed further down the scale as corrosion staining of the test coupon increases, with 4 being the worst (severe corrosion) typically appearing as a blackened test coupon.
The John Deere X320 is recommended to run 10w-30 Turf Gard oil in the motor, however any 10w-30 motor oil from a local parts store will work as well.
The John Deere G049D snow blower is designed to fit on several John Deere lawn and garden tractors, specifically the models in the 100 Series, such as the D100, D110, D120, and D130. It is also compatible with some models in the 200 Series. Always check the specific model compatibility before purchasing to ensure proper fitment.