Haynes Tech Tips - Transmission Fluid
When to change Your automatic Transmission Fluid
Most automatic transmission problems are caused by depleted (worn-out) fluid (ATF). The stresses on the ATF as it performs its dual jobs as both a hydraulic fluid and a lubricant under high temperature gradually breaks it down. Fortunately it’s easy to keep track of the fluid condition so you know when the time has come to change it.
The easiest check can be done weekly when you check the fluid level. New transmission fluid is a bright red color because it contains a dye that makes it easier to spot leaks. The fluid darkens as it breaks down and becomes contaminated.
When you pull out the dipstick, make sure the fluid is bright red, indicating it is clean. Black or brown fluid is contaminated and should be changed.
To check the fluid condition further, put a couple of drops on a white paper towel and let soak in for 30 seconds. If the fluid spreads out and maintains its red color, it’s in good condition. If the fluid is dark and doesn’t spread, it is worn out and should be changed.