Fourth Digit (number of pinion gears / LSD or Open)
2=2 Pinions Open 3=2 Pinions LSD 4=4 Pinions Open 5=4 Pinions LSD
since i haven't change to Independent Rear Suspension or IRS yet, the axle code on my car is F282...no wonder the respond feel great,the ratio is 4.3...fuh deng hehe...