* SAE 10W-30: This was a very common viscosity for that era.
* SAE 10W-40: Also common, especially in warmer climates or for higher mileage engines.
Crucially, you also need to check the owner's manual for the *type* of oil: It might specify conventional, semi-synthetic, or synthetic oil. Using the wrong type could damage your engine.
To find the correct oil:
1. Locate your owner's manual: This will have the most accurate information for your specific truck and engine.
2. Check the oil fill cap or dipstick: Sometimes there's a recommendation printed on these. However, this is secondary to the owner's manual.
3. Consult a parts store: Give them the year, make, model, and engine size of your truck, and they can help you find the correct oil.
Don't rely solely on online information. Always confirm with your owner's manual for the precise oil requirements.