Changing trans fluid on a high-mileage car -- a good idea?

I just read a thread that suggested a transmission fluid change on a (presumable) high-mileage, 9 year old car.

My son recently did the same on his Acura TL with about 230K miles on it. He doesn’t know exactly when or if the fluid was ever changed since he purchase it used 20K miles ago. Since the fluid change he has had nothing but shifting problems, causing him to replace several sensors and now it won’t even shift into reverse.

Question: is it really a good idea to change the trans fluid on a car/truck that has a high mileage and the fluid was never changed?

The fluid change did not damage the transmission, the damage was already there. This is a coincidence.

We certainly don’t always agree on fluid changes but in this case I think Tester’s method for high mileage cars makes sense. Just do a search here but it involves fluid exchange as well as a pan drop. On the other hand Honda transmissions are the week points and I always change my Acuras fluids at 30,000 miles from new and not a mile over. I get rid of them before I know if it works or not but that transmission was on borrowed time anyway.

It’s a coincidence; nothing more. He bought a well used Acura with 210k miles on it. Odds are the fluid was never changed in those 210k miles and it is going to show up at some point.Often it’s before 210k.

There’s no answer to this because mechanics don’t have crystal balls to see the future or examine what happened in the past. But common sense says clean fresh fluid is better than old dirty fluid.

I assume the transmission fluid was serviced on the Acura with 230K miles on it because the fluid appeared discolored or burnt. There’s no way to know if the transmission would have lasted another 100K miles on that fluid. Chances are, it probably wouldn’t have.

Also we don’t know if the fluid had never been changed, or if it was changed recently in an attempt to fix a slipping complaint or some other symptom. The fluid could have been changed 25K miles ago and the transmission is just worn out.

Either way, transmission failure at 230K miles is nothing unusual in the automotive world, the car has reached the end of its expected useful life. Repair or replace the car.

I would rather do it and take my chances, if it is going to kill it it would probably have had problems anyway.

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Disturbing the innards might bring up problems immediately after a trans service on a long neglected trans, things that otherwise would have come up later; but I think the odds are in the owner’s favor to do the service anyway, no matter how long it is been since the last service. There’s a better chance of solving a problem than creating one. “service” == “proper service” of course. An improper service could well cause problems. Here’s some more detailed info on the topic.