Redline 75w-90 in 1991 BMW 318i Differential

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JHZR2

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This is redline 75w-90 from the 4.10 LSD in my 1991 BMW 318i. The 318i doesnt use a standard BMW diff, it is slightly smaller and has slightly less capacity. The cover is finned, but I believe the oil gets very hot. BMW recommends Castrol XJ fluid (IIRC) which is a 75w-140 in all LSDs based upon a TSB. I refilled with a Specialty Formulations diff fluid and definitely found that the diff quieted a bit (these diffs are also known to be a bit whiny).

Code:






Sample Date 1/13/2008

Unit Age 111425m

Comp Age 111425m

Time on Oil 9925m

Oil Maint. Changed

Fluid Redline 75w90





Fe 188

Cr 2

Ni 1.2

Ti 0.6

Ag 0

Al 11

Pb 0.1

Cu 0.6

Sn 1.6

Si 166

Na 2.4

K 1.5

B 146

Ba 0.3

Mo 7.5

Mg 0

Ca 70

P 831

Zn 31

S 14997

Cd 0

Mn 3.7

V 0

Sb 0.2

Kv@40°C142.6

White Metal NONE

Babbitt NONE

Precipitate NONE

Silt NONE

Debris NONE

Dirt NONE

Appearance NORML

Odor NORML

H2O(Emul) NEG

H2O(Free) NEG
 
I felt like the 140 oil made a bit of a difference in terms of sluggishness.. The SF diff oil is more like a heavy 90wt (i.e. like a 75w-110, I believe), and works great. Id go that route before taking a full penalty of a 75w-140 in this car. THe M42 response is nice and perfect for commuting, since my current drive rarely gets all systems up to full temperature, I'd rather try to optimize operation without parasitic drags where possible.
 
~200ppm in
A VOA of the Redline would've been interesting. Contamination?

P doesn't look like a GL5.

Ask for a retest from the lab.
 
I also noticed you have a high silicon content.

Now Redline does use a lot of anti-foam, but this seems high.

Does this diffy have a breather hose?

I would not expect 188ppm for this short of a mileage. I have seen 150-250 in diffys run for 50k or better.
 
Last edited:
Originally Posted By: Steve S
Per my wifes uoa on Redline I am underwhelmed with Redline gear oil.


Good, more for the rest of us who like it.
 
What do you use now steve? Amsoil SVG like the rest of this board????
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Last edited:
Originally Posted By: MolaKule
I also noticed you have a high silicon content.

Now Redline does use a lot of anti-foam, but this seems high.


RTV from diff cover?
 
Originally Posted By: AzFireGuy79
What do you use now steve? Amsoil SVG like the rest of this board????
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Chevron DELO ESI.
 
ALWAYS send off a VIRGIN sample of oil this is the only way to even get a accurate UOA. RL used silicon af but you have no way to know anything unless a VOA is sent along
bruce
 
I am not a fan of groupthink ... but Amsoil Severe Gear is a solid performer and a worthy (not at all laughable) choice.

"Chevron DELO ESI."

Another good choice ... going to do a UOA on it?
 
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