How often should automatic transmission fluid be changed? Manufacturers typically recommend intervals ranging from every 30,000 miles to every 100,000 miles. At a minimum you should change the fluid per the manufacturer recommendations, which for most vehicles is every 30,000 miles. For vehicles with a longer fluid change interval we would not recommend going over 50,000 miles between changes in any case. Transmission fluid should be pink. If the fluid gets too dirty, replacing extremely dirty fluid with clean fluid may actually cause the automatic transmission to fail sooner. This happens because the gunk buildup in the transmission will actually help hold things together. If you flush away that gunk, you may flush away what is holding the transmission together.
If you start to notice problems with shifting such as hard shifting, high engine reving between shifts, or any other change from how the transmission has been behaving, get the fluid and transmission inspected immediately. Transmission flushes typically cost $120. Transmission rebuilding typically costs over $2000.
Transmission flushes used to be performed by dropping the pan, draining whatever fluid gravity drained (about 1/3-1/2 of total transmission fluid), and replacing the filter. Today at Wayne’s Automotive Center in Sparks Nevada we typically use a transmission fluid flush machine that will exchange all of the fluid in the transmission and back flush the filter. Consequently, the transmission fluid filter typically needs to be changed every 2nd or 3rd transmission fluid change instead of every fluid change.