How many hours on the engine? well maintained since new? or unknown? (new to you tractor) How much over "full"? Did you fill to spec (8.9 quarts/8.4 liter)? or overfill? how does your coolant look? low? Any blow-by when running? rough running/missing/hot? does oil smell like diesel? did old oil smell like diesel? what was the level like before the oil change? everything ok before the oil change? (this is new problem?) When you refilled, did you count the oil you put in the filter against the capacity? If everything was ok before, I'd say you simply overfilled based on how oil is packaged, if this is a new problem (or new to you tractor), areas to check would be coolant in the oil & head gasket leak, blow-by/worn rings, stuck injector, bad seal in injector pump, bad seal in hydraulic pump. If you didn't fill the new filter with clean oil, was the oil pump able to get a prime? (what's you oil pressure? Are the rockers hot/making noise?)