Check the owners manual and if you don't have it call the dealer. Not enough info to go on. Diesel?, Gas?, engine size?, environment temp?, Useage? eg: light duty, tow vehicle, desert, arctic etc etc....
it takes 14.5 quarts for the isuzu engine in a 2002 model year truck. steve had to find answer in owners manual.
14.5 quarts including filter
The oil capacity for a 2006 GMC W4500 diesel truck is approximately 7 quarts (or about 6.6 liters) when equipped with the 5.2L diesel engine. It's important to also consider the oil filter capacity, which can add a little more oil to the total required. Always consult the owner's manual or a service guide for the most accurate specifications for your specific vehicle.
with the 6.6l duramax 15qts. with filter change
The 2006 GMC Yukon has overhead valves (OHV).
The 2006 GMC Savana has overhead valves (OHV).
The 2006 GMC Canyon has double overhead cam (DOHC).
it is just behind the plastic dash right of the radio. it is attached to a metal braket difficult to access
The 2006 GMC Sierra-2500HD has overhead valves (OHV).
The 2006 GMC Sierra-1500 has overhead valves (OHV).
The 2006 GMC Savana-Cargo has overhead valves (OHV).
The 2006 GMC Yukon-XL has overhead valves (OHV).