Transmission kick down noise

[X5downunder]

Hi All,
Just wondering if anyone has had similar noise like my 4.4i. There is a short, "rubbing" noise when the gear downshifts, particularly when the car turns corner and starts to accelerate out of the corner or going uphill and it downshift to pick up speed.

My X5 is nearly 2 years old now. The noise was noticable when it was about 8 months old. I bought it new. After a few trips to the dealer, they finally diagnosed the problem and the fix was:...they drained the transmission oil, refill and drain it again overnight and refill again. The car was then a delight to drive again for about 6 months until about 2-3 months ago then the noise starts to return. I am taking it in next week before warranty finishes next month.

Does this sound familiar at all to any of you? Apparently, the service advisor said BMW Aust knew about the problem when they fixed it last time. My concern is if they fix it again this time round and it's only good for a few months. Then once my warranty is up, how much cost would be involved if it eventually turns out to be a major tranny problem.

Thanks for any feedback.