Originally Posted by dannyzabolotny

The important thing is to follow the official ZF procedure for filling the transmission. You have to fill the transmission with the engine running at a certain temperature, that's what a lot of people forget to do. The only time I've ever heard of a transmission failing after a fluid change is if the fluid wasn't changed correctly. You also have to use a proper OEM Filtran filter, the aftermarket ones are different internally and can cause a whining sound.

A properly done transmission fluid change will not cause the transmission to fail unless it was going to fail either way. And in a lot of cases it can actually save the transmission from dying. My 1995 750il transmission was awful when I got the car— it whined loudly on cold startup, shifted harshly, and was not smooth at all. It threw a transmission failsafe warning every once in a while too. After I changed the transmission fluid and filter all of the problems went away and it's been running smoothly for the last 12,000 miles with the new owner (who I'm friends with).