I am looking to install new rear axle in my JKR. There is 4340 ChroMo and 4140 ChroMo. 4340 is more expensive. Just wondering if its worth spending the extra cash. Anyone know much about it. I called Revolution and they said 4340 isn't needed but they do not offer 4340. Yukon axles are 4340. I don't mind spending extra is worth it.