A trim ring gear for use in an integrated drive generator has a ring gear body extending between a first end and a second end. Outer gear teeth are formed on an outer surface, and inner gear teeth are formed on an inner surface. The outer tooth roll angle at A is between 16.0 and 17.5°, at B is between 17.5 and 190°, at C is between 22.0 and 23.5°, and at D is between 23.0 and 24.5°. The inner tooth roll angle at A is between 31.5 and 33.0°, at B is between 30.0 and 31.5°, at C is between 25.5 and 27.0°, and at D is between 24.0 and 25.5°. An integrated drive generator, and a method of replacing the trim ring gear are also disclosed and claimed.