August 04, 2021
4 minutes read

This is important to know about oil

The right oil

Our 8HP demonstrates how to drive well in cars like the current BMW M5. But how do you lubricate it well so that it always stays that way? The answer to this question is both simple and complicated: with the right oil.

Oil is much more than just a lubricant. It cleans, protects, cools, cares and protects against electric shocks too. The base oil accounts for 70-80%. This determines, for example, the viscosity, the temperature behaviour or the oxidation resistance. The rest is the actual "magic ingredient" – the additives.

Oil vers. temperature

Some ensure that the oil behaves similarly over all temperature ranges. You might think it would be viscous and tough at low temperatures, but thin at high temperatures. However, viscosity and cold flow improvers intercept these properties to a certain extent… so, the transmission always shifts perfectly.

Cleaning additives keep the contaminants in suspension until they reach the filter. If the broken molecules are too small, they act as a magnet and collect the residues until they are large enough to land in the filter.

The magic of oil

In modern hybrid transmissions, additives ensure that the electrical voltage (sometimes over 300V) is not simply conducted into the transmission and control unit. They therefore also influence the conductivity of the oil.

Other magic molecules ensure that the heat generated by high loads is ideally dissipated. To do this, they literally stick to the gearbox housing with one end and thus dissipate the heat generated to the surface.These additives are also the reason why you will find advice on every bottle of LifeguardFluid 8 and 9 to shake the oil before filling, to make sure that everything is mixed cleanly. In the car this task is then taken over by the oil pump.

This mixture of high-quality base oils and additives is what makes it possible for our gearboxes to shift well, even if sometimes as much as 900Nm (as in the case of the current Audi SQ7) is thrown at them.

Because additives are responsible for comfort and are also subject to wear, in the course of time, chemically speaking, they become acidic. Therefore, we recommend a regular gearbox oil change. You’ll find more information on this topic in another article.

Last but not least, the right oil is simply able to behave in every conceivable situation, not only as the control unit expects, but also the driver (although, ideally, the driver will not even notice it is doing its magic).

About the author

Philipp Janczewski

Philipp is international service engineer, working with ZF Aftermarket since 2013. His motto as #zfexpert:

“You can never have too many horses! No matter in which engine.”