i nedd to know what the max towing capacity is for a 2004 silverado 1500 5.3L

 

book should say. do you have 2wd or 4wd?

 

to determine your tow capacity you will also need to know your differential ratio.
the code is listed on a tag in glove box on many models.

fine your code and someone on forum can tell you the ratio number.

 

Gq1 -- axle rear, std ratio
gt4 -- axle rear, 3.73 ratio
gt5 -- axle rear, 4.10 ratio
gu4 -- axle rear, 3.08 ratio
gu5 -- axle rear, 3.23 ratio
gu6 -- axle rear, 3.42 ratio
g80 -- axle rear, limited slip (positraction)

hc4 -- axle rear, 4.56 ratio

 

Look at GCWR rating thats on the rpo sticker in the glove box.

 

or check that rating on your door sticker