Trans fluid spec on 2003 Chevrolet Silverado SS

What is the OEM spec for auto trans fluid in the '03 Silverado SS, 6.0liter engine? Is it synthetic? Is it Dexron IV?

Asked by for the 2003 Chevrolet Silverado SS
Napa shows Dexron III and Dexron VI and my other catalog shows the same two choices
1 answer