As the other fellow wrote, I don't know what year YOUR X5 3.0i would be.
My Euro X5 3.0 d is a 2002 and has the NV125 transfer case (not iDrive). Transmission on mine (diesel) may not the same as the 3.0i gasoline (input torque and ratios are different between gasoline and diesel)

• roughly 3 liters/quarts total for Front/rear diffs (Redline 75w-90 Gear Oil, GL-5)
• about 1.5 to 2 liters/quarts of Manual Trans fluid (good - Redline ATF or best - Redline MTL)
• transfer case (max 1 liter/quart) of Redline ATF (good) or Redline MTL (best)

Other great news - if you have a manual 3.0 i, you can now once again get the UUC Evo 3 short shifter for your car. I just pre-ordered it for my car (same shifter for diesel & gas 3.0). Rob put it back in production - treat yourself !!!

Greg