GM manual transmissions are engineered to work with specific fluid types to ensure optimal lubrication, prevent wear, and reduce heat buildup. This guide provides a comprehensive GM Manual Transmission Fluid Chart that helps you identify the right fluid for your vehicle.
GM Manual Transmission Fluid Chart
| Transmission | Years | Fluid Type | Capacity | Notes |
|---|---|---|---|---|
| Muncie M20 | 1965–1972 | GM Synchromesh Manual Transmission Fluid | 2.75 qt | 3-speed manual, standard viscosity |
| Muncie M21 | 1965–1972 | GM Synchromesh Manual Transmission Fluid | 2.75 qt | 4-speed manual, close-ratio |
| Muncie M22 “Rock Crusher” | 1965–1972 | GM Synchromesh Manual Transmission Fluid | 2.75 qt | Heavy-duty racing transmission |
| Saginaw 3-Speed | 1970–1980 | SAE 90 Gear Oil | 2.5 qt | Common in older GM trucks |
| Saginaw 4-Speed | 1970–1980 | SAE 90 Gear Oil | 3.0 qt | Includes older Chevy and GMC pickups |
| Borg-Warner T10 | 1964–1972 | GM Synchromesh Manual Transmission Fluid | 3.0 qt | Classic muscle car 4-speed |
| Tremec T56 | 1992–2007 | 75W-90 GL-4/GL-5 Synthetic Gear Oil | 3.0–3.2 qt | High-performance 6-speed |
| Tremec TR-3650 | 2001–2010 | 75W-90 GL-4 Manual Transmission Fluid | 3.0 qt | Mustang GT 5-speed |
| Tremec TR-6060 | 2007–2015 | 75W-90 GL-4 Synthetic | 3.0 qt | Corvette, Camaro 6-speed |
| Getrag 260 | 1980–1990 | SAE 75W-90 Gear Oil | 2.8 qt | Early European-based GM cars |
| Getrag 265 | 1980–1990 | SAE 75W-90 Gear Oil | 3.0 qt | Manual 5-speed |
| New Venture NV3500 | 1988–2005 | SAE 75W-90 GL-4 Manual Transmission Fluid | 3.0 qt | Light trucks, S10, Sonoma, Blazer |
| New Venture NV3550 | 1995–2002 | SAE 75W-90 GL-4 | 3.0 qt | Upgraded NV3500 |
| New Venture NV4500 | 1991–2007 | SAE 75W-90 GL-4 | 4.0 qt | Heavy-duty trucks, 4-speed |
| GM T5 | 1982–1995 | SAE 75W-90 GL-4 | 3.0 qt | Mustangs and Camaros 5-speed |
| GM T56 Magnum | 1998–2004 | 75W-90 GL-4 Synthetic | 3.0 qt | High-performance Corvette and Camaro |
| GM 5-speed RPO | 1988–1996 | SAE 75W-90 GL-4 | 3.0 qt | F-body and Camaro/Firebird applications |
| GM 6-speed Manual | 2007–Present | 75W-90 GL-4 Synthetic | 3.0 qt | Corvette, Camaro, Silverado manual |
Note: Capacity may vary slightly depending on the year and the application. Always check your vehicle’s service manual.
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GM Manual Transmission Fluid Types
GM manual transmission fluids fall into several categories:
- Dexron/Mercon-based fluids – Some older manual transmissions use fluids similar to automatic transmission fluids (ATF), but check the specifications.
- SAE 75W-90 or 80W-90 gear oils – Common for modern manual gearboxes.
- Synchromesh-specific fluids – Designed for transmissions with synchronizers that require specific friction characteristics.
GM also specifies different fluids for different models and years. This chart is organized by transmission model, year range, and recommended fluid.
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How to Check and Replace GM Manual Transmission Fluid
- Locate the fill plug: Usually on the side of the transmission.
- Clean the area: Prevent dirt from entering the gearbox.
- Drain old fluid: Remove the drain plug or tilt the transmission (some models).
- Refill with recommended fluid: Use the exact type and capacity specified.
- Check fluid level: Top up if necessary. Transmission fluid should be level with the bottom of the fill hole.
- Test drive: Ensure smooth shifting before completing the job.
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Why Using the Correct Transmission Fluid Matters
Manual transmissions rely on the fluid to lubricate gears, bearings, and synchronizers. Using the wrong fluid can cause:
- Difficulty shifting gears
- Premature wear of internal components
- Gear slippage or noise
- Reduced efficiency and performance
GM specifies fluid types for each transmission based on gear design, friction material, and load-bearing requirements. Always follow the manufacturer’s recommendations to avoid voiding warranties or damaging the transmission.
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FAQs
What type of fluid do GM manual transmissions use?
Most GM manual transmissions use 75W-90 GL-4 gear oil or GM Synchromesh Manual Transmission Fluid. High-performance transmissions may require synthetic gear oil for extreme conditions.
Can I use automatic transmission fluid in a GM manual transmission?
Only in certain older models that explicitly specify ATF. Modern manuals almost always require gear oil with specific friction properties.
How often should I change my GM manual transmission fluid?
Typically, every 30,000–60,000 miles, but check your owner’s manual for model-specific intervals. Severe-duty use may require more frequent changes.
Is synthetic fluid better for GM manuals?
Synthetic gear oils often provide better high-temperature stability, improved gear protection, and longer service life, making them ideal for high-performance or heavy-duty vehicles.
Can I mix different brands of GM manual transmission fluids?
You should avoid mixing GL-4 and GL-5 fluids, as GL-5 oils can damage synchronizers in some manual transmissions. Stick to the fluid type recommended by GM.
Tips for Maintaining GM Manual Transmissions
- Always check for leaks around seals and gaskets.
- Use a high-quality fluid that meets GM specifications.
- Listen for grinding or clunking noises, which could indicate low fluid or worn synchronizers.
- Avoid overfilling, as excess fluid can cause foaming and shift problems.
- For performance vehicles, consider upgrading to synthetic GL-4 fluids for better protection under heat and load.
Final words
GM manual transmissions are reliable and long-lasting when properly maintained. Using the correct fluid according to your vehicle’s year, model, and transmission type is critical. This GM Manual Transmission Fluid Chart provides a clear guide to help you choose the right fluid, maintain optimal performance, and extend the life of your transmission.
