hi, i have a set of gears i just took out of my car i only put 4,000 miles on them and i could swear they are 355 when i bought them. i cant find the reciept anywhere and before i sell them i want to make sure i am right and they are not 373. how do you know? i have the ring and pinion out and i know there is a way to tell. please be specific. thanks for your help