All I can say is that the 3.7L will have the same axles; however, when the 5.3L comes on board, it will have a larger front axle for sure; not positive about the rear axle (but I did hear rumors about the next size up).
The overspinning when going over obstacles should be taken care of by the traction control system that limits the spin of the wheel in the air. Preventing the the well know axle grap...axle break or diff problems.
I really haven't heard of any problems with any of the axles other than the lapping compound problem. (I should say other than leaking drive shaft axle seals, caused by incorrect install of the axle. Hopefully, this was fixed by waking the guys up on the line and having them use the seal protector tool versus eyeing it. Easy fix at a dealer.)
I know the GM test guys did some hard testing on the vehicle prior to, and after vehicle launch.
The reason the I-5 was used was because at the time, it was the only engine available to fit in the compartment. The I-6 was too long, and production of the 5.3L was not up to the numbers they needed (and modifications were required to fit it in the engine compartment). The 3.5L was the logical engine to use, and GM has been blasted for the underpower of the engine by every magazine.
They had the 3.7L on the books prior to launch, but it takes a while to test, test and test. In a few months, the 3.5L will go out of production, and the 3.7L will take over.
I know the brand quality guy for this engine get reports everyday on any component that hits a certain number of replacements or rebuilds. This information comes from the dealers via the labor operation number for the part replaced.
This number is set pretty low, that is why with only 100+ cylinder heads replaced (out of over 100K engines on the road), the brand quality guy was all over the problem, working with engineering. Once the problem was found, the cylinder heads were stopped, which caused a shortage, and new ones with hardened valve guides were produced.
If I see a spike in the numbers (I get the labor operation number run once a month), I'll speak up.
I sure hope there is no problem, and this is just a fluke, but unless there VIN numbers are close, I can't see it as a quality spill from AAM.
Didn't know Neo and Bebe broke the front axles. Do you have photos. I would love to send them to the axle guru at GM and see what his reply is.
I would be curious to see if he tries to pound sand up my rear or give me a straight answer.