Check your Differential oils

Gamb1t · 02-20-2017, 11:36 AM

I came around to replace my wife's X1 (@58k km) differential oils (haven't done TC yet). What I found was the oil for both front and rear diff were dark and murky. Cannot see bottom.
What concerned me a bit was the low oil. ie the rear diff I managed to extract >550ml and it gulped down ~1l. Some e90 owners noticed this too with their diff oils.

Now I'm thinking did the factory underfill? If I didn't manage to suck the oils out completely which is very possible, it would've overfilled at 50%.

Anyways I replaced with BMW OSP Synthetik 75w90.

fiehlsport · 02-20-2017, 08:50 PM

Mine was yellowish/dark, it looked about right for 50,000 miles of usage. Color isn't everything, I wouldn't worry about it. Most people *never* change the diff oil and still have healthy differentials even at 100,000mi.

Have fun with the transfer case extraction, get a small tube! (flexible, but drinking straw diameter or smaller!)

0w40X1 · 02-21-2017, 12:18 AM

I sucked out rear diff with a copper tube hooked to oil dispenser plunger at about 3k miles.

Oil was about 1 liter and very clear, almost white with no particles.

I filled with Mobil 1 75w90.

It can't be overfilled unless you squirt like mad, and put plug in before it runs out to level of bottom plug.

I did this same thing to my RX8 Mazda at 3.5k miles, and while oil was white clear, it had about 1 oz. of gray metal mud I call it.

Did that one at 23k miles agin, and it had just a trace of that metal mud.

Now I'll forget them both for about 50k miles.

Diffs don't get the nasty air and contamination trouble of motor oil.

You even ran half full for awhile, and probably didn't hurt it.

Gamb1t · 02-21-2017, 12:37 PM

There will be metal shavings when it comes to metal to metal contact. Therefore it is beneficial to replace the original oil after a certain mileage. 3k miles might be a bit too early, unless it sees track time where the internal drivetrain experiences higher stress levels.

I wouldn't leave it for a long time. BMW's lifetime fluids in my skeptical mind is the lifetime of the warranty.

Wish BMW would make TC/Tranny more accessible.

0w40X1 · 02-21-2017, 08:00 PM

I drained it early to get any fine wear in metal out like I saw in my Japanese car.

I had no visible metal in my diff, and I sent off the first factory oil sample of 5k miles, and the analysis showed no metals in it.

Mostly the diff drain was to find information of how clean the oil was.

Diff can be ruined way before massive metal shavings show up (the bearings).

02-20-2017, 11:36 AM	#1
Gamb1t Major 598 Rep 1,343 Posts Drives: 330i,X1,Z4,Solstice GXP, RX-8 Join Date: Aug 2015 Location: Canukistan iTrader: (0)	Check your Differential oils I came around to replace my wife's X1 (@58k km) differential oils (haven't done TC yet). What I found was the oil for both front and rear diff were dark and murky. Cannot see bottom. What concerned me a bit was the low oil. ie the rear diff I managed to extract >550ml and it gulped down ~1l. Some e90 owners noticed this too with their diff oils. Now I'm thinking did the factory underfill? If I didn't manage to suck the oils out completely which is very possible, it would've overfilled at 50%. Anyways I replaced with BMW OSP Synthetik 75w90.
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02-20-2017, 08:50 PM	#2
fiehlsport Second Lieutenant 49 Rep 283 Posts Drives: '13 X1 xDrive35i Join Date: Sep 2015 Location: Endwell, NY iTrader: (1)	Mine was yellowish/dark, it looked about right for 50,000 miles of usage. Color isn't everything, I wouldn't worry about it. Most people never change the diff oil and still have healthy differentials even at 100,000mi. Have fun with the transfer case extraction, get a small tube! (flexible, but drinking straw diameter or smaller!)
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02-21-2017, 12:18 AM	#3
0w40X1 Lieutenant 34 Rep 485 Posts Drives: 2014 BMW X1 s28i M Sport Join Date: Sep 2013 Location: West Texas iTrader: (0)	I sucked out rear diff with a copper tube hooked to oil dispenser plunger at about 3k miles. Oil was about 1 liter and very clear, almost white with no particles. I filled with Mobil 1 75w90. It can't be overfilled unless you squirt like mad, and put plug in before it runs out to level of bottom plug. I did this same thing to my RX8 Mazda at 3.5k miles, and while oil was white clear, it had about 1 oz. of gray metal mud I call it. Did that one at 23k miles agin, and it had just a trace of that metal mud. Now I'll forget them both for about 50k miles. Diffs don't get the nasty air and contamination trouble of motor oil. You even ran half full for awhile, and probably didn't hurt it.
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02-21-2017, 12:37 PM	#4
Gamb1t Major 598 Rep 1,343 Posts Drives: 330i,X1,Z4,Solstice GXP, RX-8 Join Date: Aug 2015 Location: Canukistan iTrader: (0)	There will be metal shavings when it comes to metal to metal contact. Therefore it is beneficial to replace the original oil after a certain mileage. 3k miles might be a bit too early, unless it sees track time where the internal drivetrain experiences higher stress levels. I wouldn't leave it for a long time. BMW's lifetime fluids in my skeptical mind is the lifetime of the warranty. Wish BMW would make TC/Tranny more accessible.
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02-21-2017, 08:00 PM	#5
0w40X1 Lieutenant 34 Rep 485 Posts Drives: 2014 BMW X1 s28i M Sport Join Date: Sep 2013 Location: West Texas iTrader: (0)	I drained it early to get any fine wear in metal out like I saw in my Japanese car. I had no visible metal in my diff, and I sent off the first factory oil sample of 5k miles, and the analysis showed no metals in it. Mostly the diff drain was to find information of how clean the oil was. Diff can be ruined way before massive metal shavings show up (the bearings).
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