To change or not to change....yet.

[Big "J"]

I have a 2003 3.0 with 70k and am wondering if I really need to change my tranny fluid and filter just yet. I know BMW says it's lifetime fluid but, I don't really buy that. I read where some wait to change them every 30K or only at 100K.

What are some indications that would prompt me to go ahead and change the fluid to prevent further damage and prolong the tranny's life?

And is there a good website to buy the synthetic fluid for less, rather than going to a stealer and paying an outragous price?

Thanks in advance!!!