At what mileage should I change or flush the trasmission fluid. I get different answers at the dealer.

Depending on the make and model, it is recommended anywhere from 50,000 to 150,000 miles. Other variables include operating temperatures, and how hard the transmission is worked. In a normal passenger car, not used for towing, I would personally recommend changing it at 100,000. There is a lot of different views on this subject but consider the kind of use your transmission gets. Examples would be heavy loads or a lot of city stop and go driving.

Thanks Mark, your answer has been the best and made more sense than any of the answers the dealers themselves gave! Very much appreciated!! Its a 2011 Hyundai Sonata 2.0T. I use it in more city stop and go traffic daily. You know the everyday type traffic one takes to and from work. My baby does NOT do heavy loads. Thanks again for your help!

I am glad to see that answer also. I have a 2010 Sonata with 112k miles and never changed the fluid yet. When I took it to local dealer to get fluid changed, he said with that many miles and no previous change, to just not change it because it would cause more problems and possible failure if change fluid. I never drive it like the severe use states in the manual. He would not even drain and fill. So I will find a garage that will do the drain and fill and go from there

I'd just flush it every 30k. Transmissions are like mechanical watches with friction points, except that they operate at high temperatures. All transmission fluid is, is a version of lubricating oil with red dye in and other properties needed in today's trannies. What would make one think that it is OK to allow this fluid to become dirty!? Du-ha, change the trans fluid or pay big buck on the back end.