I'm A Bonehead! Differential Vs. Transfer Case Screw Up
 

2007 E70 X5 4.8i
112,000 miles.

After finishing a mechatronic sleeve change it was recommended to change the transfer case fluid. I just finished this morning and it has been bothering me that after draining red looking fluid from what I THOUGHT was the transfer case, I now realize that was the front differential. Looks like I'm back under the X5 tomorrow.

2 questions:

1. Just so I don't screw up again, there are front and rear differentials and the transfer case is just aft of the transmission?

2. I only drove about a mile with the front differential having transfer case oil in it, that shouldn't be a problem right?

Looks like I'm draining that front diff again and putting the correct fluid in it unless I hear a majority tell me transfer case oil is fine in a differential. I'm sure I already know the answer.

That was a waste of a $50 liter bottle of transfer case oil :(

1. Yes
2. Yes
If you put diff fluid in the TC that may not end good, but the other way around is a relatively safe scenario given you caught the mistake on time-and you did.

Id prolly drive 100 and drain and refill

Thank you both for the reply. ARD - do you mean you would service the mistake correctly, drive a 100 miles and then drain and refill again?

Yes. But probably not essential. I'm nutty about fluids. Just get things up to temp, any old fluid would be dissolved into the new fill. Drain an then add 100% proper fill.