Have you ever wondered why different types of transmission fluid are made for your vehicle’s gearbox? Various contributing factors in these two types of transmission fluid impact the performance and longevity of the gearbox of an engine system.
A synthetic transmission fluid vs regular fluid comparison reveals the core differences in usage, making, chemical composition, and gearbox performance. However, the prime difference is the quality, where synthetic fluids are more refined than regular mineral fluids.
To know more about the differences between these transmission fluids, you might follow through with this article till the end. And thus, you can decide wisely which fluid to use in your vehicle’s transmission system.
Synthetic Transmission Fluid Vs Regular: Comparison Chart
The following provides various major differences at a glance between synthetic transmission fluid and regular (mineral) fluid.
Synthetic Transmission Fluid | Regular Transmission Fluid |
Viscosity Index | |
High | Low |
Chemical Degradation Index | |
Low | High |
Friction Control | |
High | Low |
Temperature Control | |
High | Low |
Thickness | |
Low | High |
Cost Effectiveness | |
Low | High |
Although all types of transmission fluids possess an identical formulation. But the amount and quality of fluids and other additives create a massive change in the fluid performance.
Viscosity Index
The viscosity of transmission fluid refers to how friction deficient it is with the surface of the components inside the gearbox. In general, a low viscosity index is ideal for transmission systems.
Synthetic transmission fluids are comparatively more refined than regular fluids. As a result, the amount of impurities and contaminants in synthetic fluids is much lesser. Therefore the viscosity of the fluid also becomes lower than that of regular or mineral transmission fluids.
The newer automatic transmission system uses synthetic fluids as standard. ATF or automatic transmission fluids work better, keeping the small gears and components safe from intense friction. Hence, regular transmission fluids are more workable on manual or stick-shift gearboxes.
Chemical Stability
The chemical stability of the transmission fluid refers to the rate of molecular breakdown after a certain period. Due to the more refined quality of the synthetic transmission fluids, it is more chemically stable.
Thus, the synthetic fluid’s working period or longevity is almost double compared to regular transmission fluids. The oxidation rate is higher in mineral fluids, making them less stable and degrade very early.
Therefore using conventional transmission fluids require more fluid flushing and replacement, which can be very cost ineffective. Sludge, varnish or oxides, corrosion, a decrease in viscosity, and poor gearbox performance are all consequences of oil degeneration.
That is why it is never to use conventional or manual transmission fluids in an automatic transmission system.
Friction Control
The formulation of newer synthetic transmission fluids is composed of high-grade and premium-quality oil. This enhances the lubricating quality of the transmission fluids, causing a more subtle surface layer between the bearings and gears inside the transmission system.
As a result, the friction outcome inside the gearbox is very less, and a smooth transmission between different gear shifting is observed. On the other hand, regular transmission fluids cannot comply much with friction control.
That is why using mineral fluids in an automatic transmission cannot be fruitful, as it may result in hard shifting and damage to the components. Automatic transmission having torque converter should always be fed with high-grade ATFs.
Temperature Control
We all know to overheat and increasing temperature is not good news for motor vehicles. And it also goes for the transmission system. n engine gearbox contains many big and small units of gears and bearings. When in operation, all these rotates continuously being touched with others.
Hence, it is quite natural that friction between the metallic moving parts generates heat. Here comes the part of transmission fluid which actively absorbs the excess heat and helps maintain the temperature by minimizing the friction between them.
Due to a lesser viscosity index and specific gravity, synthetic transmission fluids are more capable of temperature reduction than regular fluids.
Physical Thickness
Accumulating the transmission fluids on a surface with time can be degrading for the moving components of the gearbox. Hence, the thinner and less viscous the fluid is, the better it is for the transmission system.
Refined synthetic hydrocarbons in mineral transmission oil are less thick than regular fluids. Therefore, the fluid flow, in contrast to the metallic surface, is smooth, making it better and more effective in enhancing the shift pattern of the gearbox.
The manual transmission system uses thicker conventional transmission fluids using a hand-driven shifting pattern while not using a torque converter.
Cost Effectiveness
Naturally, the production cost of synthetic transmission fluid is way ahead of conventional fluids due to high grade, refined oil use, and additives. Therefore the retail price is high as well compared to regular fluids.
But the quality, longevity, and performance of the synthetic transmission fluids are worth it as it requires less maintenance and improves gearbox lifespan.
Frequently Asked Questions (FAQs)
Should I change the synthetic transmission fluid?
If your existing transmission fluid is outdated, you can use synthetic transmission fluids in your vehicle’s gearbox. For synthetic fluids, it does not matter what type of transmission system your vehicle possesses. But it is mandatory to use factory-recommended transmission fluid and flush the system perfectly before pouring a new grade transmission fluid.
What is synthetic transmission fluid?
Synthetic transmission fluids are mineral lubricating oils specially formulated for small gearbox components. It uses high-grade, premium, and more refined quality synthetic hydrocarbon, which increases the transmission system’s overall performance, longevity, and smoothness.
Can you mix fully synthetic transmission fluid with regular?
Both synthetic and mineral fluids have core hydrocarbon material in the formulation. Therefore, you can mix a fully synthetic transmission fluid with regular. But the rate percentage of the quality, additives, etc., can make a huge difference in the performance. That is why mixing different types of transmission fluids is not recommended.
Can you use synthetic transmission fluid in older cars?
Synthetic transmission fluids are an upgraded version of conventional mineral fluids. It uses refined and high-quality synthetic hydrocarbons for better performance. Thus there is no issue in using fully synthetic transmission fluid in older cars, provided you have flushed the system entirely.
How often should synthetic transmission fluid be changed?
Synthetic transmission fluids are made for a higher working lifespan. Hence, you might change the fluid after driving the vehicle every 60000 miles or more. In case of rough and extreme vehicle use, you can change the fluid after 30000 to 50000 miles to stay safe and maintain gearbox quality.
Which Transmission Fluid To Choose And Why?
Now comes the big question about which transmission fluid you should feed your beloved vehicle. It depends upon the transmission system and the manufacturing company’s recommendation. Nowadays, automobile companies specify the grade and type of transmission fluid to be fed to the transmission system.
Since most vehicles nowadays use an automatic transmission system, getting authorized ATFs or products from branded fluid manufacturers is better for smooth shifting performance.
But if your vehicle is older, having a stick shift or manual gearbox, you can conveniently use regular or semi-synthetic transmission fluids.
The core formulation or all transmission fluids are similar, you can mix various fluids. Using them in case of emergency can be acceptable, but it is not advisable to do so.
Changing the transmission fluid of the gearbox is one of the most crucial parts of the regular vehicular maintenance procedure. But as a beginner, it is important to know and have a clear concept about synthetic transmission fluid vs regular fluid comparison.
Using the wrong grade or type of transmission fluid in the system can actively cause irreversible damage to the gearbox and its components. And the repair cost of the transmission system is exceptionally expensive.
Lastly, you might wonder that is synthetic transmission fluid worth it. If budget is not a problem, you should always use synthetic transmission fluids in most transmission systems after flushing properly. It will enhance not only the shifting performance but also the rate of fluid replacement from time to time.
You Can Also Read:
- Is Transfer Case Fluid The Same As Transmission Fluid? A Detailed Explanation
- How to Find What Type of Transmission Fluid Do I Need?
- Transmission Fluid Compatibility Chart Explained for All Vehicles
- Differential Fluid Color Chart Explained For Better Maintenance

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