What Oil do i need for my Transmission

[Franck from Moscow]

Everything is in the title....

I want to change oil of my transmission but i don't really know which should y use......

My transmission is a GM5 and my X is from 2003 approaching the 100.000Km

I already know that my old oils green/blue/olive color, what made me surprised frankly speaking.

But i have read that Dexron III (rose/red color) should fit my transmission caracteristics.

Not so long ago i went to my BMW service and the guy told me that they already use Dexron VI (first time i hear about it......).

There for i am a bite lost in so many contradictions and colors.

What would u recommand and from which brand ???

I have heard that Motul is the best for transmission, true ????? or Castrol maybe ?????????