The importance of ATF quality
The quality of the Automatic transmission fluid (ATF) used is key to extending the life of the automatic gearbox, and therefore that of the vehicle. But it is not only important that the oil is of quality, if it is not accompanied by proper maintenance of it, replacing it when necessary.
An ATF in poor condition drags metallic particles through the gearbox that can cause breakdowns, which generally involve a high cost compared to performing regular maintenance.
Characteristics of a good ATF
ATF for automatic transmissions is much more specific and much more complex than other hydraulic oils. The automatic transmission has to make thousands of changes between clutches and discs with controlled friction between its materials while resisting oxidation at the high revolutions of the torque converter and its stator.
Inside the transmission are dozens of electronic sensors, to which the oil has to transmit small currents to indicate pressures and conditions. Valves operate between different ‘rubber’ seals that are susceptible to the softening or drying offered by oil. This requires high detergency and solvency.
- Have a correct coefficient of friction to respond to specific materials.
- Is not corrosive to parts and materials.
- Maintain thermal stability – an automatic transmission has to operate between -40℃ and + 80℃, occasionally going over 90℃. The oil has to have a very high viscosity index for this.
- Have a good detergency.
- Possess stability against oxidation.
How to check the ATF
Checking the ATF level in an automatic vehicle is similar to how the engine oil level is checked. The only difference is that it checks while the engine is running.
When we verify the ATF, we must check both the level and the quality of it. Although both are important, an excessively low ATF level can cause more serious damage than if the ATF quality is poor.
In any case, if we detect that the transmission fluid smells burnt or appears brown, it must urgently be replaced.
When to change the automatic transmission oil?
The ATF oil in an automatic transmission deteriorates over time. There are some factors that cause this deterioration to be faster, such as:
- Driving in the city that forces you to stop regularly due to traffic.
- Carry heavy loads on the vehicle.
- Carry trailers.
The reason the fluid deteriorates is because the transmission gets hotter as it runs. The hotter the fluid is heated, the more wear it causes on the transmission itself, forcing the gears to work harder.
When to replace the transmission oil depends on the manufacturer and the type of box. In general, TCMatic advise to replace the oil:
- 60,000 km for DCT and CVT transmissions
- 80,000 km for the rest of automatic transmissions, whilst always taking into account the transmission manufacturer’s advice.
TCMatic maintenance kits always come with manufacturer approved oils. If you’re unsure as to what the best oil choice is for the vehicle you’re working on call Drive/Train by Express Spares on 046 901 0136.