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The sheer amount of misunderstanding between gear oil and transmission fluid is surprising. I didn’t know it until recently when we spoke with a few of our loyal followers about what kind of products they’d like us to feature in the aforementioned niche.
The communication was a little bizarre because some replies from our readers elicited that they didn’t know the difference between gear oil and transmission-related fluids. That being said, none of the people at ‘My Engine Needs’ mean to insult our readers’ intelligence. It’s just that we never thought that gear oil and transmission would be so much of an issue, to begin with.
This post is a comparison style write-up concerning ‘What I need to know about gear oil and transmission fluids.’ I’d rather you read it and then get back to us through the comments section or personal emails. That is if you have any questions about gear oil and vice versa.
Gear Oil and Transmission Fluids are a Different Thing:
Despite the difference, their context can be a little confusing. Take it this way, manual transmission vs. automatic transmission. What comes to your mind first? With a manual transmission, you’d think about a manual old school gearbox. For automatic transmission, we know that the context is automatic cars that don’t involve a manual gear. In the latter case, the gear shifts automatically once a cycle is complete.
In some sense, if we break it down to their physical form, both gear oil and transmission oil are just plain ol’ “oil.” Of course, their chemical composition, viscosity, and resistance to temperature is different. But, we are dealing with oils in the long run. They essentially do the same job, with the exception of different mechanical environment.
Transmission Fluid/ Oil Vs Gear Oil – Which One is Better?
A lot of weblogs stress upon the use of transmission oil. Other websites recommend gear oil. In that order, the element of preference comes down to the actual application of the product. If you have a manual transmission car, you’re going to have to use gear oil. Period. There’s no denying to that.
If you have an automatic vehicle, you’ll need high-quality transmission fluid. What matters is their efficiency. Those websites that only emphasize on the use of either gear oil, or transmission fluid, do so because they are probably marketing the product. However, common sense prevails in all cases. If you have a manual transmission car, go get a bottle of gear oil. Don’t let that “website” confuse you.
Let’s talk about the application of gear oil for manual cars.
- Formulated to maintain excellent low temperature fluid protection
- Helps provide outstanding thermal stability for cleanliness and longer service life
What Do I Need to Know about Manual Gearboxes?
My personal favorite is always going to be a manual transmission. The first reason is the confidence factor because you have the gear shifting at your disposal. You know when to change the gear, especially if you are driving on a very challenging road. I like to take control in my own hands, so, I am always going to prefer manual gearboxes over the automatic transmission. Maybe it’s old school mentality, but I like it that way.
- Enhanced friction durability for smooth transmission performance
- Meets DEXRON-III H requirements and satisfies requirements of DEXRON, DEXRON-III, IIE and II
We have talked about viscosity in some of our previous posts. If you don’t recall that, you can check out some of the synthetic motor oil reviews. Viscosity is the thickness of a fluid. When we talk about oils, the thickness density determines a few factors.
If the oil is too thick, it may cause the engine to “struggle” a lot. You will notice that despite acceleration, the car doesn’t respond in terms of speed. I did a little experiment last week and mixed synthetic motorcycle oil with synthetic motorcar oil and used it on my motorcycle. The results are disappointing. Although the motorcycle engine sounds smooth, it does not respond too well to acceleration input.
Anyhow, wherever gear oil is concerned, viscosity matters a lot. Gear oil usually has low viscosity. It helps to shift the gear quickly, whilst supporting the fragile transmission mechanism. Gear oil comes in the following grades:
- 0W/5 to 5W/10
Beneath the gear stick, there is an entire gear transmission system that is depending on the gear oil viscosity. In that sense, the viscosity of the gear oil has to support the intricate transmission network to impact the vehicle’s movement.
Automatic Gear Transmission:
Since you all know, gear shift automatically in automatic transmission. It depends on the engine requirements and the throttle effect. However, for the mechanism to work, the transmission oil has to perform its job. Otherwise, gears won’t shift and there might be delayed responses whenever the driver attempts to shift up or shift down.
The transmission fluid lubricates the engine transmission whenever the engine demands it. As compared to manual gear transmission, the car engine demands gear shift whenever automatic transmission requires it. Therefore, the gear shifting system does not depend on your input entirely.
For automatic transmission vehicles, the transmission fluid has to exhibit the following properties:
- High Film Strength Helps to Dramatically Reduce Heat and Wear
- Automatic Transmissions Generate a Great Deal of Heat and Depend on Transmission Fluid for Cooling and Protection
This one’s a common attribute in both gear oil and transmission fluids. The viscosity of transmission fluid is much lower than that of synthetic and non-synthetic engine oil. Likewise, the viscosity of automatic transmission fluid is maintained around 0/5W to 5W/10. It is more than enough.
Generally speaking, both gear oil and transmission fluid last a lot longer as compared to engine oil. The changing intervals prevail over several months on end. The only difference in transmission fluid use case is the challenge where lubrication has to be maintained whenever gears are shifted up and down.
For transmission fluid to be effective, it has to be resistant to heat. On the other hand, gear oils are also resistant to heat. Both of these oil types act more like coolant when it comes to keeping the temperatures maintained at an all-time low. If you are on the lookout for transmission fluid or gear oil for that matter, make sure that the oil does not reach boiling point easily.
If the fluid/oil heats up too early, it can aggravate the metal-on-metal damage cases. Obviously, low viscosity is a challenge. No matter which brand you go for, you need to make sure that your gear transmission is not affected by the low viscosity of the gear oil and/or transmission fluid. That’s the key takeaway from this entire discussion.
By comparison, gear oil is slightly thicker than transmission fluid. That does not imply that gear oil has lower viscosity. It’s just that the chemical composition of gear oils is different from the transmission fluid. Therefore, don’t make the mistake of switching gear oil for transmission fluid. Both of them are meant for their respective mechanical environments.
Last update on 2020-07-02 / Affiliate links / Images from Amazon Product Advertising API