How often should I be changing my transmission fluid?

Dear Car Talk

Dear Car Talk | Apr 01, 1995

Dear Tom and Ray:

I have been taking my '78 VW Scirocco to those instant oil change places for years. Maybe that's why I have 126,000 miles on it and it still runs great! Lately, these instant oil change places have increased the number of services they offer. They now check your air filter, transmission fluid, etc. Every time I bring my car to this one place, they show me a drop of black colored liquid (it looks and feels like engine oil) which they tell me is my transmission fluid. They say it's black and dirty because it hasn't been changed in a while and ought to be (for about $20). Should I change my transmission fluid. And if so, how often?

RAY: I think you should change it, Malcomb. And if it were my car, I'd change it every 30,000 miles or so.

TOM: Manufacturers recommend a variety of intervals, ranging from 30,000 miles to never (actually, the recommendation is "never or when the transmission dies, whichever comes first"). But if you want to keep your car forever, you should change the transmission fluid regularly.

RAY: There are two good reasons to change it. First, all oils simply break down over time. Second, during the life of the car, little fragments of the transmission get broken off due to wear and tear. And it's good to get them out of there so they don't float around and cause damage to other parts of the transmission.

TOM: What will be interesting is to see what happens AFTER you change it. The next time you go to that oil change place, will they still come over with a drop of black, colored liquid and tell you your transmission fluid needs to be changed?

RAY: If they do, we'll know this is all a ruse, and that black oily stuff didn't come from your car...but actually from the juice bar at the health food store down the street.

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