The Allison 1000 is a widely used automatic transmission in heavy-duty trucks, particularly in GM Duramax diesels such as the Chevy Silverado 2500/3500 and GMC Sierra.
Using proper transmission fluid affects not just lubrication but also shift quality, wear resistance, heat control, corrosion protection, and service life.
Transmission Fluid for Allison 1000
1. Castrol TranSynd 668 Full-Synthetic Automatic Transmission Fluid
Key Features:
- TES 668™ approved
- Excellent thermal stability for high temperatures
- Superior friction durability for smooth shifting
- Helps extend fluid and filter service intervals
- Designed for heavy-duty towing and hauling
2. OIL1G-X XCALLIBER Synthetic ATF
Key Features:
- Meets Allison transmission performance requirements
- Synthetic formula for enhanced wear protection
- Good oxidation and thermal stability
- Compatible with transmissions originally filled with approved ATFs
- Positive user feedback for everyday use
Related Allison Transmission Fluid Capacity Chart(All Models)
3. Mobil Delvac Synthetic Automatic Transmission Fluid
Key Features:
- TES 295™ approved
- Full synthetic for high-temperature protection
- Excellent anti-wear properties for heavy loads
- Good cold-start fluid flow
- Trusted choice for professional and DIY use
4. Valvoline MaxLife Multi-Vehicle Full Synthetic ATF
Key Features:
- Full synthetic for improved durability over conventional fluids
- Maintains smooth shifting with age
- Good oxidation resistance and stability
- More affordable than premium Allison-approved fluids
- Suitable for daily driving and moderate towing
5. AutoTrans Super Plus Full Synthetic ATF
Key Features:
- TES 295 compatible
- Full synthetic for stability under load
- Provides anti-wear and anti-oxidation protection
- Compatible with many automatic transmissions
- Affordable choice for fluid changes
Related Allison 4000 Transmission Fluid Capacity(For All Series)
Allison Recommendations
Allison Transmission recommends using TES 668™ and TES 295™ automatic transmission fluids for the Allison 1000. These fluids are engineered to meet specific performance standards that extend transmission life and improve overall performance.
- TES 668™ – The latest Allison-approved fluid, offering improved friction stability and durability.
- TES 295™ – A classic Allison-approved fluid that provides long service life and reliable performance.
- TES 389™ and DEXRON®-VI fluids – Older or substitute fluids that can be used in some cases, but do not offer the extended service intervals or anti-wear performance of TES 295 or TES 668.
For long life, heat resistance, and heavy towing, TES 668 or TES 295 is recommended.
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How to Choose the Right Fluid
Go OEM When Possible
Using TES 668 or TES 295 approved fluids ensures the highest level of protection and service life for the Allison 1000.
Consider Your Usage
- Heavy towing, high temperatures, or frequent off-road use: prefer TES 668 or TES 295 full synthetic fluids.
- General driving with occasional towing: synthetic ATFs such as Valvoline MaxLife may suffice if official approval is not required.
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Fluid Change Intervals Matter
Allison-approved fluids typically allow longer intervals between services compared to generic ATFs, reducing maintenance frequency.
Check Specifications
Even popular fluids may claim compatibility without being officially Allison-approved. Always confirm that the fluid matches TES 668 or TES 295 specifications.
FAQs
Can you use DEXRON VI in Allison 1000 transmission?
DEXRON VI can be used in an Allison 1000 transmission in certain cases, but it is not recommended as the primary fluid. Allison-approved TES 668 or TES 295 fluids are preferred because they provide superior wear protection, friction stability, and extended service life.
What type of transmission is the Allison 1000?
The Allison 1000 is a heavy-duty, electronically controlled, 6-speed automatic transmission. It is commonly used in diesel trucks, commercial vehicles, and SUVs requiring high torque and durability.
How to check transmission fluid in Allison 1000?
To check the transmission fluid:
- Warm up the vehicle to normal operating temperature.
- Park on a level surface and apply the parking brake.
- Locate the transmission dipstick (if equipped) or consult the manufacturer’s procedure.
- Remove the dipstick, wipe it clean, reinsert it fully, and then remove it again to check the fluid level.
- Fluid should be at the correct mark and have a red or pink color; dark or burnt-smelling fluid indicates it may need changing.
How much fluid does an Allison 1000 hold with a torque converter?
An Allison 1000 transmission with a torque converter typically holds approximately 13 to 15 quarts (12.3 to 14.2 liters) of transmission fluid. Always check the manufacturer’s specifications for exact capacity based on the vehicle and configuration.
What is the best transmission fluid for the Allison 1000?
The best transmission fluids are Allison-approved TES 668 and TES 295. TES 668 is the latest specification and offers the best friction stability, thermal protection, and wear resistance. TES 295 is also approved and widely used, but TES 668 is recommended for newer or high-demand applications.
How many quarts of transmission fluid are in an Allison 1000?
The Allison 1000 transmission generally holds about 13 to 15 quarts of fluid including the torque converter. The exact amount can vary slightly depending on the specific vehicle model and whether a full drain or refill is performed.
Final Thoughts
The Allison 1000 transmission requires high-quality fluid designed to handle heat, heavy loads, and long-term use. Using Allison-approved TES 668 or TES 295 fluids will ensure smooth shifting, extended transmission life, and reliable performance. Options such as Castrol TranSynd 668, Mobil Delvac TES 295, and other high-quality synthetic ATFs provide protection and performance for heavy-duty trucks under all conditions.
