A method of replacing a governor and inversion pump drive gear comprising the steps of: removing an existing governor and inversion pump drive gear from an integrated drive generator having an input shaft, a gear differential including a carrier shaft and the gear differential including a ring gear for driving a generator, said ring gear also connected for driving an accessory drive gear, said accessory drive gear connected to drive the existing governor and inversion pump drive gear; and replacing the existing governor and inversion pump drive gear with a replacement governor and inversion pump drive gear including a gear body extending between a first end and a second end and having a disc extending radially outwardly, and a boss extending from said disc toward said second end, and having splines in an internal bore, and a shat extending from said disc toward said second end, a flange on said shaft, and drive gear teeth formed on said flange, there being input gear teeth outwardly of an outer diameter of said disc, said input gear teeth having a gear tooth profile with roll angles at points A, B, C, and D, wherein the roll angle at point A is at a maximum form diameter, the roll angle at point B is 20 percent away from point A and toward point D, the roll angle at point C is 80 percent away from point A and toward point D, and the roll angle at point D is at the outer diameter of the gear tooth, and the input gear profile having a roll angle at point A between 20.9 and 22.3 degrees, a roll angle at point B between 22.7 and 24.2 degrees, a roll angle at point C being between 28.2 and 29.7 degrees, and a roll angle at point D being between 30.0 and 31.5 degrees, and said drive gear teeth having a gear tooth profile defined by roll angles at points A, B, C and D, with a drive gear tooth profile at point A having a roll angle of between 14.7 and 16.2 degrees, a roll angle at point B of between 18.7 and 20.2 degrees, a roll angle at point C of between 30.3 and 31.8 degrees, and a roll angle at point D of between 34.2 and 35.7 degrees; wherein there are 62 of said input gear teeth; wherein said input gear teeth have a pitch diameter of 3.683 centimeters (1.45 inches) +/-.025 centimeter (.01 inch); wherein said input gear teeth have an outer diameter of 8.128 centimeters (3.20 inches) +/-.025 centimeter (.01 inch); wherein said input gear teeth have an outer diameter of 8.128 centimeters (3.20 inches) +/-.025 centimeter (.01 inch); and wherein said outer gear teeth have a pitch diameter of 3.683 centimeters (1.45 inches) +/-.025 centimeter (.01 inch); wherein the roll angle at point A is 15.6, the roll angle at point B is 19.5, the roll angle at point C is 31.1 degrees, and the roll angle at point D is 35.0 degrees. removing an existing governor and inversion pump drive gear from an integrated drive generator having an input shaft, a gear differential including a carrier shaft and the gear differential including a ring gear for driving a generator, said ring gear also connected for driving an accessory drive gear, said accessory drive gear connected to drive the existing governor and inversion pump drive gear; and replacing the existing governor and inversion pump drive gear with a replacement governor and inversion pump drive gear including a gear body extending between a first end and a second end and having a disc extending radially outwardly, and a boss extending from said disc toward said second end, and having splines in an internal bore, and a shat extending from said disc toward said second end, a flange on said shaft, and drive gear teeth formed on said flange, there being input gear teeth outwardly of an outer diameter of said disc, said input gear teeth having a gear tooth profile with roll angles at points A, B, C, and D, wherein the roll angle at point A is at a maximum form diameter, the roll angle at point B is 20 percent away from point A and toward point D, the roll angle at point C is 80 percent away from point A and toward point D, and the roll angle at point D is at the outer diameter of the gear tooth, and the input gear profile having a roll angle at point A between 20.9 and 22.3 degrees, a roll angle at point B between 22.7 and 24.2 degrees, a roll angle at point C being between 28.2 and 29.7 degrees, and a roll angle at point D being between 30.0 and 31.5 degrees, and said drive gear teeth having a gear tooth profile defined by roll angles at points A, B, C and D, with a drive gear tooth profile at point A having a roll angle of between 14.7 and 16.2 degrees, a roll angle at point B of between 18.7 and 20.2 degrees, a roll angle at point C of between 30.3 and 31.8 degrees, and a roll angle at point D of between 34.2 and 35.7 degrees; wherein there are 62 of said input gear teeth; wherein said input gear teeth have a pitch diameter of 3.683 centimeters (1.45 inches) +/-.025 centimeter (.01 inch); wherein said input gear teeth have an outer diameter of 8.128 centimeters (3.20 inches) +/-.025 centimeter (.01 inch); wherein said input gear teeth have an outer diameter of 8.128 centimeters (3.20 inches) +/-.025 centimeter (.01 inch); and wherein said outer gear teeth have a pitch diameter of 3.683 centimeters (1.45 inches) +/-.025 centimeter (.01 inch); wherein the roll angle at point A is 15.6, the roll angle at point B is 19.5, the roll angle at point C is 31.1 degrees, and the roll angle at point D is 35.0 degrees.