[ga9213]

BMW Specs front differential to use the G2 fluid (GL-5) which is fine, but the rear calls for G1 (GL-4) which I'm a little confused by... Seems GL-5 would be better suited for a hypoid differential.

Anyone know why BMW would specify a GL-4 fluid? Is there some reason I wouldn't want to use the same GL-5 I use for the front for the rear as well?

[Barbera335]

Not sure of the reasoning but I used GL5 front and rear on my X3 at 60k and again at 120k and it has been fine. Take that for what it is worth.

[one9kilo]

Originally Posted by Barbera335

Not sure of the reasoning but I used GL5 front and rear on my X3 at 60k and again at 120k and it has been fine. Take that for what it is worth.

Same. I used GL-5 (75w90) for both front and rear. BMW made a change suggesting to use different fluid for front and rear. Before the change, they were the same for front and rear so it really shouldn't matter much if you do use the same fluids.

You can do both front and rear with just 2 quarts.