Can Synthetic ATF Be Used In Older Cars?

A common question is whether synthetic ATF can be used in classic cars? Yes, synthetic automatic transmission fluid is certainly compatible with older transmissions. It can provide a nice performance and protection upgrade.

Synthetic ATF will have similar viscosity and frictional properties to conventional ATF. Make sure to purchase an ATF meeting the correct specification for your transmission (more on that below).

The additive package of modern ATF (whether conventional or synthetic) will be significant upgrade over previous generations of ATF.

Factors To Consider Before Changing Automatic Transmission Fluid In Older Cars

• When changing ATF in any transmission, consider if the transmission may have significant deposits. If the transmission fluid hasn’t been changed in several years, performing a flush would be a good idea. We offer the superb AMSOIL Engine and Transmission Flush for this very task.
• Is the transmission original or rebuilt? Is it functioning properly?
• Are the seals in good shape? Should any leaky seals be replaced at this point?
• Replace the pan gasket and transmission filter during this process.

Does Synthetic ATF Cause Leaks?

This is a common misconception. Synthetic ATF does not cause leaks. In fact, good synthetics like AMSOIL will condition seals and extend their lifespan.

Conventional ATF may have a thicker viscosity in cooler temperatures. Synthetic ATF has a fairly consistent viscosity across the temperature spectrum. This difference could potentially lead to more drips on the garage floor through leaky seals. Therefore, this factor is what could fuel the “synthetic ATF causes leaks” myth.

How To Choose The Correct ATF For Classic Cars

See our article “How To Find The Right ATF For Older Cars”. Or check out our online application guide. If you still have questions, contact us using the form on this page. Put your question in the “Questions or Comments” section.

In conclusion, modern synthetic ATF products are perfectly compatible with mechanically sound older transmissions. In fact, they can improve transmission performance and maximize wear protection.