Use SAE 5W-40 full synthetic heavy duty diesel oil in the engine, Mobil 1 Synthetic Multi-Vehicle ATF in the transmission and power steering system, and Mobil 1 synthetic SAE 75W-140 gear oil in the differential. Together, these changes should increase fuel mileage 8 to 10%, save your turbo from sudden death, and allow your truck to last a long time.

Additional thoughts on using a bypass oil filtration system:

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