2016 Chevrolet Silverado 3500HD: Transmission Fluid & Service

Quick answer

• Transmission make/model: Allison 1000 6-speed automatic (LCT1000)
• OEM fluid spec: DEXRON-VI
• Drain & fill capacity: Approximately 7.4 quarts (7.0 liters)
• Full overhaul capacity: Approximately 12.7 quarts (12.0 liters)
• Filter OEM part number: GM Part #24228707 (Verify with dealer or service manual)
• Recommended service interval: 45,000 miles (severe service) or 90,000 miles (normal service)

Fluid type explained

The Allison 1000 transmission in the 2016 Chevrolet Silverado 3500HD requires a fluid that meets the DEXRON-VI specification. This is a significant change from earlier Allison transmissions that used the Allison-specific TES-295 or TES-389 fluids. Using the wrong fluid can cause shifting problems, overheating, and premature clutch wear.

DEXRON-VI is a synthetic fluid that provides superior performance and protection compared to conventional fluids. It offers better oxidation resistance, improved friction durability, and more consistent viscosity in extreme temperatures. This ensures smooth shifts and long-term transmission health.

Service procedure

There are two common ways to service your Allison transmission: a drain and fill, or a full fluid exchange.

• Drain & Fill: This is the simpler method and is what most shops and DIYers will perform. It involves draining the fluid from the transmission pan, replacing the external spin-on filter, and refilling with fresh fluid. This typically replaces about 7-8 quarts of the system's total fluid, leaving the old fluid in the torque converter and cooler lines.

• Full Fluid Exchange: A full exchange uses a specialized machine to pump out all of the old fluid while simultaneously adding new fluid. This method replaces nearly 100% of the fluid in the system. While more thorough, it is also more expensive and requires specialized equipment.

For the Allison 1000, a simple drain and fill combined with a filter change is the manufacturer-recommended procedure and is sufficient to maintain transmission health.

Service interval

Chevrolet provides two service intervals based on how the truck is used:

• Severe Duty: The severe service interval is 45,000 miles. This applies if you frequently tow heavy trailers, haul loads at or near the truck's GVWR, or operate in extreme conditions (mountains, off-road, city traffic). Most 3500HD trucks will fall under this category.

• Normal Duty: The normal service interval is 90,000 miles. This is for trucks that are primarily used for unloaded highway driving, which is rare for a one-ton dually.

Given the capabilities of a Silverado 3500HD, it is always best to follow the severe duty service interval to ensure the longevity of your transmission.

Common transmission problems

The Allison 1000 is a robust and reliable transmission, but some issues can still arise, especially on higher mileage trucks.

• Solenoid Failure: A failed solenoid can cause harsh shifting, delayed engagement, or being stuck in one gear. This is a common issue on many automatic transmissions.
• Torque Converter Issues: Problems with the torque converter can lead to shuddering, slipping, or a "no-move" condition.
• "Limp Mode": If the transmission control module (TCM) detects a serious fault, it may put the transmission into "limp mode," where it will be stuck in a single gear to prevent further damage. This is a protective measure and requires immediate diagnosis.

Sticking to the recommended service schedule with the correct fluid and filter is the best way to prevent these common problems.

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