I have had 3 wheels aluminum crack by valve stem but gmc tells me no one else has had that problem!! Has anyone else ever had this problem?
Sometimes a wheel can be damaged by improper lug nut tightening when the wheel is installed on the truck. Try to find a shop that will install wheels using a manual torque wrench, hand tightening the lug nuts in 3 rounds following the recommended sequence, rather than a torque stick or impact wrench.
I don’t see any TSB’s directly related to cracks by the valve stems, however these bulletins might be of interest.
18-03-10-006F: Tire goes flat due to wheel corrosion
05-03-10-003: wheel porosity
08-03-10-004: tire mounting procedures
Is the crack in the alloy itself?