Hello. This procedure is not too difficult once it is explained. First make sure you have the correct fluid as this is usually is not normal ATF fluid but a special fluid from bmw. The fluid part no. is located on the transmission on a sticker and this is the type of fluid you will need for your transmission. Disregard the part of the instructions that say about the tester and getting to a certain temp. This is not needed.
First drain the fluid from the drain plug. Then fill the trans from the fill plug until it runs over. When the fluid runs over install the fill plug loosely. Then you will need to start the engine and then quickly go back, unscrew the fill plug and continue filling the transmission with the engine running. This should be done right away as quickly as possible. When the fluid again runs over the fill hole, install the fill scew and you are done.I hope this helps. Thank you in advance for your accept.
BMW Mechanic
Level 1 BMW Master Certification, 9 Years Dealer experience, Team Leader, Shop Foreman