I would pass on the Lucas 75W-80 and use a better oil. OEM oil is 75W-90 synthetic (BMW SAF-XO). Consider running a quality 75W-90 synthetic from Redline, Valvoline, Castrol, or Mobil 1.

Also, there is no issue running a gear oil with friction modifiers in an open differential.

Edit: looks like the 75W-80 was a typo in your post title. Regardless, the Lucas is considered lower tier. If you want to buy at an auto parts store, go with Mobil 1 or Valvoline.

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2007 E70 4.8i