Problems with 2010 Infiniti QX56 SUSPENSION

I have been the owner of this vehicle since june of 2014 and purchased it with 53k miles. the underbody has substantial rust for the age of the vehicle. this rust has seized the alignment bolts in the rear of the vehicle and it cannot be properly aligned without major repairs(in excess of $1500). a vehicle of this age should not have corrosion to the extent that a rear end alignment is not possible. i have two other vehicles substantially older with less underbody corrosion. i believe the coating/parts used are defective and when i contacted infiniti they refused to compensate or make the repairs. this is troublesome as the alignment can affect the stability of the vehicle and could result in a accident. *tr

A fault code gets set and deactivates the rear air leveling suspension. when that happens, no air to the air shocks and it bottoms out. supposedly, only the dealer can reset it. a real problem when towing a trailer. and even worse, there is no driver alert when it happens or after it has happened -- you just loose your rear suspension. very dangerous. this has happened 3 times for me in the last 3 weeks -- each time i have towed a trailer i need to take it back to the dealer to have it reset. they tried to replace the air pump, but that did not work. the dealer initially blamed an over loaded trailer -- but the trailer was weighed and shown not to be overloaded. my complaint has to do with the fact that the suspension is intentionally completely deactivated by this fault code and their are no warnings provided that it is deactivated. *tr