2015 Chevy silverado 1500 lt crew can how to figure out what my rear axle ratio is

Look into you glove box and see a stick with alot of numbers and letter if u see gt4 is 3.73 If not more likely u might have a 3.42 the reason why bc most 2WD come with 3.42 or a 3.08 always look into ypur glove box that tags is your parts codes u can look it up anytime what parts your truck is need before buying the wrong part.