Modern day vehicles are mounted with a wide variety of different transmissions. They are primarily used for speed and power adaption between the engine and drive axle, for speed compensation between axles and wheels, or for changing direction in the power train. It is differentiated between manual transmission, automatic transmission, double clutch transmissions, steering gear and hydraulic systems and between gears of cars and commercial vehicles. When selecting the right transmission oil in the course of a transmission change or transmission repair, the transmission type plays the decisive role.
Requirements for gear oils
- Lubrication / wear protection
- High friction stability
- Oxidation stability
- Excellent foaming and air release behavior
- High fuel-efficiency
- Good properties of shifting / low cold viscosity
- Corrosion protection
- High thermal stability
- Long drain intervals or even fill-for-life
- No noise, chatter damping
- High shear stability
- Compatibility with electric components/elements
- Loadcarrying capacity (EP = Extreme Pressure)
- Release contaminant and deposits
These diverse requirements of a modern transmission to the lubricant can only be met if, from an application engineering point of view, the correct lubricant is used in the required quantity in the permissible operating condition in the transmission. It is therefore important to pay close attention to the relevant specifications and OEM approvals for gearbox repairs and gear oil changes.
Gear oil types
As one of the leading lubricant developers and suppliers in the automotive industry, FUCHS offers a broad portfolio of dedicated gear oils thanks to its in-depth know-how.
Manual Transmission Fluids (MTF)
In modern manual transmissions, the lubricant performs a wide variety of tasks in addition to classic wear protection and also has a significant influence on driving and shifting comfort. In particular, material compatibility with regard to the synchromesh materials used plays a major role in manual transmissions.
Axle transmissions place particularly high demands on the oils used, especially with regards to wear protection (AW) and pressure pressure properties (EP). In addition, axle oils must also have very good aging properties. Here, too, longer and longer change intervals up to fill-for-life must be achieved. With stricter emission regulations and directives, axle oils are also increasingly becoming the focus of efficiency optimization in the powertrain.
Automatic Transmission Fluids (ATF)
The coefficient of friction when opening and closing the oil-lubricated multi-disc clutches and brakes in automatic transmissions is important for the functionality of an automatic transmission and the corresponding shifting comfort. This is exactly what automatic transmission oils need to be exactly tuned to. Due to the different requirements of the manufacturers of automatic transmissions regarding the friction coefficient characteristics, no general classification has been established. The OEM specifications are decisive for automatic transmission oils.
Transmission oils for continuously variable transmissions (CVTF)
Transmission fluids for continuously variable transmissions (CVTFs) are very similar to ATFs. However, in addition to the ATF properties, they are specially adapted to the necessary friction properties for contact between the metallic friction partners (variator to chain/drive link belt). Since powerful hydraulic pumps are usually used in CVT transmissions, corresponding CVTFs must have particularly good foaming properties and good air release capability to prevent cavitation in the pump.
Double clutch transmission fluids (DCTF)
Double clutch transmissions generally consist of a dual clutch (either dry or wet) and two "half" manual transmissions. Due to this design, double clutch transmission fluids (DCTFs) combine the properties of an excellent MTF and a high-performance ATF. In addition, the use of hydraulic pumps increases the requirements for foam resistance.
Transfer case fluids (TCF)
Transfer case fluids (TCFs) are used in the transmission types of the same name, for example in all-wheel drive vehicles.
Transfer cases themselves consist of different components (differential, clutch, etc.), so that the oils used have to meet the most diverse and in part individual requirements. The main focus here is on excellent friction behavior as well as wear protection and shear stability.
How to find the right oil for your vehicle
Get an overview of our wide range of gear oils for passenger cars and commercial vehicles in our > product finder.
With the > oil chooser from FUCHS you reach step by step the optimum lubricant for your vehicle.
You are looking for further lubricants, e. g. engine oils, antifreezes, brake fluids, etc. Please use our > product assistent.
Good to know:
"Fill-for-Life" with automatic transmission oils
The first-filled automatic transmission fluid usually remains in the engine over the entire life of the vehicle. Only in the event of a repair of the gearbox there will be a gear oil change. FUCHS recommends a regular check of the oil level - preferably with every engine oil change in a specialist workshop.
However, automatic transmissions and the used automatic transmission fluids are often exposed to difficult and severe conditions. High operating temperatures e.g. can lead to increased wear of the gear oil and to significant losses in shifting ease.
In this case a change of the automatic transmission oil can lead to a significant improvement. But it is quite important that all the remains of the old filling are flushed out. FUCHS offers special equipment for all interested workshops.
In any case, on the one hand the drain intervals of the manufacturer as well as the exact quantities are to be considered exactly. After all, automatic transmissions are very sensitive to both over- and under-filling. The FUCHS oil chooser offers you exact information about suitable automatic transmission fluids and the right quantities.