What does it do?
Transmission fluid works as both a lubricating oil, as well as a hydraulic fluid that aids in the transmissions shifting of gears, and aids in cooling the transmission.
Why does it need replacing?
Transmission fluid degrades over time, particularly with harder driving conditions. Since the transmission handles all gear shifts, the fluid is subjected to degradation. Stop-and-go city driving, towing heavy loads, and other hard use will cause the fluid to degrade faster.
When should it be replaced?
Tranmission fluid should be replaced according to your vehicle's recommended maintenance. For Subaru vehicles, this is typically 100,000 km, as part of Service D. Ask your Whitby Subaru service advisor for advice on replacing the transmission fluid on your vehicle based on your driving habits.