In 1999 Chevrolet released a new pickup bearing a familiar name: the Silverado. In 1999 and 2000, Chevrolet offered the classic C- and K-series trucks alongside the new Silverado pickups. In 2001, the Silverado replaced the C- and K-series trucks altogether. The 2005 Silverado came in three sizes, 1500, 2500HD and 3500HD. Chevrolet gave customers many options on all three versions of the 2005 Silverado, so knowing the correct fluids to add to the truck components is imperative.
General Motors recommends 5W-30 conventional engine oil on all models of the 2005 Chevrolet Silverado, in most cases. In extreme weather -- temperatures that fall below -20 degrees F -- GM recommends 5W-30 or 0W-30 synthetic engine oil. In all cases, check that the American Petroleum Institute certified the oil and that it meets GM Standard GM6094M.
All of the 2005 Silverado's engines use a special coolant, Dex-Cool. General Motors recommends using only Dex-Cool coolant and clean water mixed at a 50-50 ratio.
The brake system uses a hydraulic fluid to pressurize the brake system when you press the brake pedal. General Motors recommends using Delco Supreme 11 or an equivalent DOT-3 brake fluid to fill the 2005 Silverado's master cylinder.
The 2005 Silverado had a hydraulic clutch system. General Motors recommends using the maker's own hydraulic fluid -- GM Part No. 12345347 -- or an equivalent DOT-3 brake fluid in a Silverado equipped with a five-speed transmission.
On 2005 Silverado's fitted with a six-speed transmission, GM recommends using its own fluid -- GM Part No. 88958860 -- or super DOT-4
Manual Transmission Fluid
The 2005 Silverado has three manual transmission options: five-speed with low gear, five-speed without low gear and six-speed. The five-speed manual transmission with low gear uses GM Goodwrench Synthetic manual transmission fluid or equivalent 75W-85 GL-4 gear oil.
On 2005 Silverado's with a five-speed manual transmission without low gear, General Motors recommends only synchromesh transmission fluid.
Some 2005 Silverados have a heavy-duty Allison transmission. In these Silverados, General Motors recommends filling it with any synthetic transmission fluid that meets Allison Transmission specification TES-295. If you shop at the dealership, you can ask for GM part No. 12378515.
Automatic Transmission Fluid
All versions of the 2005 Chevrolet Silverado that have an automatic transmission use Dexron-III transmission fluid. There are many manufacturers of Dexron-III transmission fluid, so check that the fluid label reads "Approved for the H-Specification."
The 2005 Silverado has to available rear axles, standard and steerable. The standard rear axle uses 75W-90 synthetic gear oil. The steerable rear axle uses synthetic gear oil, just as the standard axle does, but GM recommends using its own brand of oil -- GM part No. 12378557.
The 2005 Silverado with four-wheel drive uses 80W-90 gear oil. GM recommends using only he all-wheel drive front axle 75W-90 synthetic gear oil.
Transfer Case Fluid
The 2005 Silverado with a manual transfer case requires Dexron-III transmission fluid approved for H-specification.
Silverados with an automatic transfer case and four-wheel drive use Auto-Trak II fluid in its transfer case. If the Silverado has all-wheel drive and an automatic transfer case, GM recommends using only Dexron-III transmission fluid approved for H-specification.