Rationale for deviating from BMW recommended oil specs & service intervals

[svenson]

I think that is the same as the transfer case too. Just use a siphon and do your best. I would definitely search youtube and forums to see if there are any tips or tutorials before you perform it.

transfer,i have a drain plug ,its easy..done it already.
unfortunately there isnt another way.that or do a service in the whole differential which costs a lot and plus i dont want to replace the OEM one with no problem occurring.

 

[CleanSump]

Transfer case is easy. Differential may be hard to get to the plug if you have a spare tire underneath like our X3 does. But a cut off Allen wrench with a combo wrench gets you past that.
Do the diff after you drive somewhere to warm the oil good. Otherwise is sucks out very sloooooow. Use a flexible thin tube so you can get it to angle down to the bottom.

 

[f355spider]

transfer,i have a drain plug ,its easy..done it already.
unfortunately there isnt another way.that or do a service in the whole differential which costs a lot and plus i dont want to replace the OEM one with no problem occurring.

Wow, that is different than my G30 M550ix. No drain plug on the transfer case or front diff, just fill, but have drain and fill plugs on the rear diff. Unfortunately you just make do with what you can get. CleanSump is correct that is should be warm and use a thin tube siphon. There are a lot of videos of it being done on various BMWs on youtube.

 

[altaylar]

1- Winter rating. not viscosity. 1 is not close to right.
2- for pure fuel economy reasons correct
3- not only 30 or 40wt but a euro spec oil.
4- pretty close to right
5- I do feel they are pretty aggressive with regards to length of oil interval.. also depends on driving conditions, climate etc.

Quoted what I replied to in case of edit:

Exactly. OP's reasoning is accurate. Only add is, he wants a euro spec oil, not an API 30 grade