right from chevys website
What Is Not Covered All the above items are not covered for damage due to accident, misuse, alteration, insufficient or improper maintenance, contaminated or poor quality fuel. Medium-duty trucks, including the C4500, are excluded from this powertrain coverage. For complete details, refer to your Warranty and Owner Assistance Information booklet.
An Important Note about Alterations and Warranties Installations or alterations to the original equipment vehicle (or chassis) as distributed by General Motors are not covered by the General Motors New Vehicle Limited Warranty. The special body company, assembler, equipment installer or upfitter is solely responsible for warranties on the body or equipment and any alterations (or any effect of the alterations) to any of the parts, components, systems, or assemblies installed by GM. General Motors is not responsible for the safety or quality of design features, materials or workmanship of any alterations by such suppliers.
To summarize, missuse and alterations voids the warranty. Also; non GM calibrations voids the warranty. GM aftermarket parts installed by an authorized dealer voids GM's warranty related to whatever they install. Missuse is a broad term but may include using your launch TCS feature, racing, no lift shifts, anything really. So if you add/replace anything that would increase preformance 99% the dealership will take note and deny your claim.