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Description
No doubt, modifying your truck is part of the fun, but when it really counts, proper maintenance is what keeps it alive. Run high-quality oil and use filters designed for your fluids and powertrain, and you'll be set up for hundreds of thousands of reliable, trouble-free miles.
Using the proper fluids and staying on top of service intervals is critical for injector health, cooling efficiency, and long-term durability, especially on high-mileage LB7 trucks.
Factory Fluid Capacities & Recommended Weights
Engine Oil (6.6L Duramax)- Capacity: 10 quarts (with filter)
- Recommended Oil: 15W-40 diesel engine oil
- Cold Climate Option: 5W-40 synthetic
- Service Fill: 7.4 Quarts
- Total Capacity: 12.7 Quarts
- Recommended Fluid: Allison approved TES-668 or TES-295
- Capacity: 5.8 quarts
- Recommended Fluid: GM TranSynd Full Synthetic
- Capacity: 2 quarts
- Recommended Fluid: Dexron III ATF (Manual Shift) Auto-Trak II (AutoTrac)
- Capacity: 1.75 quarts
- Recommended Fluid: 75W-90 gear oil
- Capacity: 3.2–4.3 quarts ( Varies by model year)
- Recommended Fluid: SAE 75W-90
Proper filtration and OEM-spec fluids help protect critical components like injectors, turbocharger, and transmission while extending the life of your Duramax.