Ancient wisdom says you should change your transmission fluid every few years, with different car brands suggesting intervals between 30,000 and 100,000 miles as the sweet spot. But what happens when you buy a used car with a lot of mileage on its clock that’s never had its transmission fluid changed?
On May 16, TikTok user Alex “the Car Doctor” (@alexthecardoctor), a seasoned mechanic, weighed in on this issue while responding to a viewer question.
“A lot factors go into play when choosing to change your transmission fluid or not,” he began, using a Chevy Equinox boasting 247,000 miles as an example. If you’ve been religious about changing the fluid, he advises to keep up the good work.
But for those who’ve just bought a high-mileage car with a murky maintenance past, Alex offers different advice: “Leave it alone, because it’s probably gonna go out.”
Alex especially warns against flushing, calling it “very dangerous,” and instead suggested a drain and fill for cars without a clear fluid change history. “But if you flush it, it’s almost a guarantee it’s not going to work,” he further cautions.
The video has since garnered over 24,000 views, with viewers having a lot to say in the comment section.
@alexthecardoctor Replying to @irishblack95 Should You Change Your Transmission Fluid? #transmission #mechanicsoftiktok #transmissionfluid ♬ original sound – Alex The Car Doctor
One commenter wrote, “Drain and fill is the way!”
Another added, “If you’re changing it 40-50k then keep doing it. If not just add more as needed.”
“never flush just drain and refill,” a third commenter wrote.
So… should you bother with the transmission fluid?
According to Cars.com, the best way to find out whether you should change the transmission fluid is to take a look at it: “The concern is that if the fluid appears to be past its prime—dark-colored, smelling burnt or with metal flecks in it—then it may be best to leave it alone. Why? Because it probably looks that way due to wear in the transmission.”
The article further states, “That bad fluid may have a ‘sticky’ quality to it or metal flecks that act to aid friction, and if it’s changed, the new fluid might cause the transmission to start slipping.”
Alex is not the only one to grapple with this question on TikTok. Recently, another TikToker went viral after breaking down the difference in maintenance requirements for manual transmissions, automatic transmissions with serviceable filters, and automatic transmissions with non-serviceable filters.
The Daily Dot has reached out to Alex via TikTok comment.
