Engine Oil in Gearbox: is it an Efficient Alternative to Transmission Fluid?
Young drivers sometimes wonder whether it is possible to use the engine oil as a lubricant for transmission parts. This is due to the fact that modern engine oils are designed for heavy loads and also include a wide range of active chemical additives for operation under severe conditions. In this article we will address this question.
Today, you can find a large number of lubricant
brands for automobiles on the market. No wonder that some people come up with
the question whether these lubricants are interchangeable or not.
First of all, it is necessary to determine what types of lubricants are available on the market. Generally, all car lubricants can be divided into two big groups – engine oil and transmission fluid. Lubricants for transmissions, in turn, fall into manual transmission fluids and automatic transmission fluids (ATF). It is interesting to note that automatic transmission fluids can be used in manual transmissions. Learn more about it in the following video:
In terms of composition, engine oils and
transmission fluids can be the following:
- Mineral;
- Synthetic;
- Semi-synthetic.
Difference between transmission fluid and engine oil
First of all, manufacturers of car lubricants produce engine and transmission oils separately. In addition, each type of lubricants has its own unique characteristics. Components for engine and transmission fluids are designed taking into account operating conditions under which these lubricants will be used. Engine oils and transmission fluids (for manual and automatic transmissions) operate under completely different conditions.
The main difference between engine oils and
transmission fluids lie in the following:
- Different temperature conditions
Motor lubricants are exposed to very high temperatures, both normal and extreme loads, and interact with combustion products. However, even in such severe conditions, engine oils must effectively protect the loaded friction pairs, remove heat, flush and retain wear products, protect parts from corrosion, etc. Transmission fluids, in turn, do not have to deal with severe temperature differences and do not interact with hostile environments. However, transmission fluids are exposed to much higher loads.
- Viscosity characteristics;
Transmission fluids have a higher level of
viscosity than motor oils. Transmissions of modern cars are quite complex in
terms of design and engine oil (due to its viscosity level) cannot ensure a
full-scale functionality of the transmission. The enhanced viscosity allows the
lubricating film, formed by the oil on wearing surfaces, to withstand higher
loads and to provide reliable protection to transmission parts.
- Set of additives.
Taking into account the intended purposes,
engine and transmission oils contain completely different sets of additives.
ATF oils used in automatic transmissions are more functional due to the complexity
of modern automatic transmissions.
It should also be noted that the transmission
oil must be changed less frequently than the engine oil (for transmission fluid
it is after 60-80 thousand kilometers with manual transmissions and approx. 40
thousand kilometers with automatic transmissions).
How to determine the
type of oil?
If you have a large number of bottles (canisters) with different types of fluid, it may become a problem to find the vessel with the transmission fluid if the label comes off. Only experienced mechanics can determine the type of oil by sight, and the transmission fluid smell may be distorted after a long period of time. But there is one method which will help even inexperienced drivers to determine what’s in the bottle (canister):
- Add a drop of unidentified oil in the water;
- If the drop of oil holds its shape and it remains on the water surface for several minutes, then it is the engine oil;
- If the drop spreads out, forms a thin film and becomes iridescent – it is the transmission fluid.
Engine oil in automatic transmissions
If we are talking about automatic transmissions
(or CVTs), then it’s better to give up the idea to use engine oils, even in
emergency cases when ATF level in your transmission is critically low because
of some failures and the only solution you have is a bottle of engine oil. The
thing is that automatic transmissions are extremely sensitive to the type of
ATF used. You may have problems even if you use ATF fluids (which have not been
recommended by the transmission manufacturer).
Learn how important it is to use the right type of ATF for automatic transmissions
Engine oil in manual
transmissions
As for manual and semi-automatic transmissions, the use of engine oil may seem quite possible. At some internet auto-forums you can even find the information that some drivers use engine oils instead of ATF and do not have to deal with any negative consequences. Taking into account the abovementioned information about engine and transmission oils, it becomes clear that although some characteristics and properties of lubricants for these two units are similar, these types oil belong to absolutely different groups.
However, it is possible to use the engine oil for manual transmissions in front-wheel drive cars, but it is allowed only for a short-time, otherwise this step will significantly reduce the service life of the manual transmission. As for rear-wheel cars equipped with manual transmissions, the use of engine oil instead of transmission fluid is absolutely unacceptable. It will lead to strong wear or even failure of the transmission only after a few thousand kilometers.
In case of emergency (car accident) you can add the engine oil in the manual gearbox. But it is important to understand that it is the least-evil measure. With such a mixture inside the transmission, you should reach the nearest repair shop as soon as possible and by no means continue using your car for a long period of time. Finally, we have to note that if, for one reason or another, your transmission is filled with the engine oil (fully or partially), all oil must be drained as soon as possible. Then, you should fill the transmission of your car with the type of transmission fluid recommended by the car manufacturer.
P.S. If you come up with the opposing idea to use the transmission fluid in the engine of your car, then check out the following video:
