Originally Posted by Renboy
That is completely wrong. Auto tranny fluid should be changed in regular intervals no different than, oil, brake fluid, ps fluid, diff oil, etc. It goes through heat cycles just like any of the other fluids and does degrade causing air bubbles to be trapped in it which increases the temp of the fluid, and causes seals to swell. Once the old fluid is replaced, the seals are no longer as swollen and leaks develop. Changing the fluid before it gets to that stage prevents these leaks and other problems. Lifetime fluid only exists if you are satisfied with a 160k km life expectancy for your tranny.
bmw has a specially formulated oil that they use in their tranny that they stress not be changed.
while your right about changing oil's in trannys it does not apply here.