Can You Mix Synthetic & Mineral Based Transmission Oil?

by Jay Motes
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Synthetic transmission fluid is a type of transmission fluid that offers some advantages over mineral-based transmission fluids. Synthetic transmission fluid is less likely to break down from the high levels of heat in a transmission and will protect the transmission longer.


Mixing mineral-based and synthetic transmission fluid is acceptable, according to Mobil and Valvoline, both of which manufacturer synthetic and mineral-based fluid for a variety of vehicles. Manufacturers even sell prepackaged blends of synthetic and mineral-based transmission fluid.


Car owner's may want to mix transmission fluid when adding fluid to a low transmission. Because synthetic transmission fluid is more expensive than conventional transmission fluid, mixing synthetic and mineral-based fluid when the fluid is changed is a way to cut cost while gaining some of the advantages of synthetic transmission fluid.


Whether the transmission fluid is synthetic or mineral-based, it is important to use the proper transmission fluid designed for your vehicle. The manufacturer's recommendation on the proper type of transmission fluid to be used is in the owner's manual for the vehicle.

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