I have an automatic and I was listening to one of the guys at work and he was saying how "beneficial" a transmission flush can be. He also said its always good to change the differential fluids at every 30k. I know BMW wants you to do this...

Is there any real benefit to doing these?

 

Yes, it is beneficial. Your gear oil can get sludgy over time and should be changed. I've heard people say not to completely flush your transmission fluid in one interval because it's very fine and can harm the gears. It's best to simply let it drain then refill every few thousand miles.

 

changing fluids is apart of car maintenance....

 

Do not flush your transmission it will shock it causing damage. Just drain and refill drive and and then again when your doing your oil change.

 

Sounds Good, thanks for the advice..I knew there was something about the flush vs. draining. Ill be changing the rear diff this weekend...I was just going to use Toyota rear diff fluid, any other suggestions