'99 Gears

What are the gears in a '99 silverado? It has the 5.3L 325 engine.

My guess, 3.73's. But look at the RPO build sheet in your glove box (sticker on the inside of the glovebox door itself) for the letters GT4 (code for 3.73's) Could have 3.42's (GU6) or 4.10's (GT5)