Transmission Fluid - To Change or Not To Change?



My 1998 Ford Taurus SE has 110,000 miles on it and has never had an automatic transmission flush or drain/replace. No transmission problems yet (knock wood). What I’ve learned from Googling: 1. Never flush. 2. Drain/replace every 30K. 3. If the vehicle has over 100K and the tranny fluid has never been changed, don’t do anything or risk causing major problems. Is this last bit of advice true? Should I leave well enough alone or have the dealer drain/replace?


Definitely go with #2, drain & replace. This service includes dropping the oil pan and servicing the filter. Do not let yourself get slickered into a transmission flush, which is a different service. The advice to “do nothing” is not to be taken seriously.


Agree! Flush definitely not recommended. Drain & filter change with necssary adjustments should give you a long life. The folklore is that servicing the transmission will dislodge “false seals” formed by debris. There is some grain of truth in this, but if there is that much debris, the transmission would be on its last legs. Also, a normal leak should be fixed, and should not break the bank. The flush would likely cause more damage than it supposedly cures.


Drain and replace. It will cost you less to have them pretend to do it than having a pretend flush done. Worst case scenario. Usually they do the actual draining.


The folklore is that servicing the transmission will dislodge “false seals” formed by debris.

I believe this folklore is the result of so many drivers ignoring automatic transmissions until they start causing problems. When someone does a fluid change because they already have noticed problems it is common that the fluid change is not going to fix the problem. As a result the change is done and the problem is still there and the transmissions soon fails as it would have without the change.


Good explanation Joseph!


After changing the fluid reset the PCM by disconnecting the battery for a half hour or pulling the PCM fuse for that length of time. This will reset the adaptive shifting settings. I have been told that you can damage the clutches by changing from very old fluid with friction modifiers depleted to new fluid.

Be absolutely sure you use the correct fluid. You can very easily trash your trans by changing with the wrong fluid!!! I wonder how much this myth has been influenced by improper fluid being used.


find a reputable tranmission shop near you. go there. get their honest (and if you have recommendations as to their reputation) recommendation.

DONT go to the dealer. you will pay double, and that is really unnecessary!