5W-30 is Recommended.Regards HHH
5w30 conventional or synthetic is your choice.
The 2004 Chevrolet Corvette has overhead valves (OHV).
The 2004 Chevrolet Suburban has overhead valves (OHV).
The 2004 Chevrolet Impala has overhead valves (OHV).
The 2004 Chevrolet Tahoe has overhead valves (OHV).
The 2004 Chevrolet Express has overhead valves (OHV).
The 2004 Chevrolet Malibu has double overhead cam (DOHC).
The 2004 Chevrolet Colorado has double overhead cam (DOHC).
"80-90" weight gear oil. Brand not important.
The 2004 Chevrolet Express-Cargo has overhead valves (OHV).
The 2004 Chevrolet Silverado-2500HD has overhead valves (OHV).
The 2004 Chevrolet Silverado-1500 has overhead valves (OHV).