Each make and model is different, and you should always refer to your vehicle’s ownership manual for specific maintenance requirements related to your vehicle. Our Toyota service team can also give you personalized insight about the condition of your transmission fluid and the need for service currently. One way that we can do this is by looking at the consistency and color of the transmission fluid. Thick, murky fluid should be replaced as soon as possible. A smart guideline to use as a rule of thumb is to change or flush the fluid approximately every 45,000 miles or three years.