* SF, SG, SH, SJ, or SL: Your owner's manual should specify the correct oil rating. These older ratings are suitable for your truck, but modern oils (SM and above) are generally backwards compatible and offer better protection. However, you don't necessarily *need* the latest oil.
* Viscosity: The viscosity (weight) of the oil is crucial. Check your owner's manual for the recommended viscosity grade, but a common recommendation for older trucks like yours, especially in moderate climates, is 10W-30. If you experience very cold winters, 5W-30 might be a better choice. If you frequently tow heavy loads or operate in extremely hot climates, 20W-40 could be considered.
* Conventional vs. Synthetic: Conventional oil is perfectly acceptable for your truck and will be less expensive. Synthetic oil offers better protection and longer life but is more costly. The choice is yours depending on your budget and preferences.
In summary: Start by checking your owner's manual for the manufacturer's specific recommendation. If you don't have the manual, a good starting point is 10W-30 conventional oil rated SF, SG, SH, SJ, or SL. You can also use a modern oil (SM or higher) with that viscosity. Always use the appropriate oil filter for your truck.
