Myths and Truths about Automatic Transmission Oil

The first myth about automatic transmission oil is that "it never needs to be replaced". False! Heat degrades the oil, which over time fills with metallic particles and can absorb moisture, losing its lubricating properties. The oil should be replaced every 62,137 miles, and it can be checked from the cap: if it is red/pink, it is fine; if it is brownish, it needs replacing; if it is black, the transmission is suffering.

The second myth is that changing the oil will break the transmission. This myth circulates because if the oil is black and sludgy, it can mask the wear of the clutches, providing artificial friction; clean oil removes this kind of "carpet" and the transmission starts to slip, but the fault lies not with the oil but with the neglected maintenance that led the transmission to that point.

Then there is the question: is a complete flush or partial replacement better? The rule is: if the oil is just worn, both can be done. If it is black and very burnt, it is better to do only the partial replacement, as a complete flush would shift all those residues into the valve body, risking clogging it and truly breaking everything.

Finally, always use the specific oil indicated by the manufacturer. When parking, put it in neutral, pull the handbrake, and then put it in "P", so the weight of the car does not remain loaded on the transmission mechanisms, and do not shift from "D" to "R" while the car is still moving.