What Diff Oil Should Be Used on Open Diff and LSD

[RUS_ZHP]

Hi Family,

What diff oil are you running and why did you chose that viscosity?
In case of the LSD, does anybody have an experience with 75W-140?
I have LSD and not sure which way to go: 75W-110 or 75W-140. I know that recommended oil for e46 M3 and e38 M5 is 75W-140. MFactory recommended that to me as well. He is the message:
"Fluid viscosity should be thickened if any competitive driving is being done. We recommend any high quality synthetic 75w140. Our go-to fluid is Torco but we understand that it might be difficult for some customers to find in their region.
When in doubt, Motul is always a choice we recommend."

Diffsonline is recommending to stay with 75W-110.
I think 75W-140 will be an overkill and not ideal during the cold New England winters.
Thoughts?

[az3579]

I've traditionally used Redline 75W-90 in the open factory diff. Then when I switched to the Diffsonline Clutch-type LSD, the diff made a lot of noise when turning when using the 75W-90 fluid.

After some research, I found out Diffsonline requires 75W-110 fluid in this particular diff, so I switched to Redline 75W-110 and haven't had any issues with noise since. I have driven it in the winter and summer temps with no issues to report.

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[Reasoned1]

I have an MFactory helical LSD, and I use 75W-90 (Redline)—as recommended by MFactory. No noise whatsoever...

[ZHPizza]

Really depends on if you have a Helical kr or clutch type diff

[zhp05jb]

Another Red Line 57904 (75W90) Synthetic Gear Oil user on stock diff. No noise.

[RUS_ZHP]

Thank you for the feedback and thoughts.
I have helical LSD and leaning towards 75w-110.
I will report back once I'll switch to that oil type. Most likely it will be Red Line.
I forgot to mention that on my wife's car with stock 3.64 diff I am using Red Line 79w-90 and everyting is great.

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[GeorgeH]

BMW recommended SAF-XO 75W90 on open diffs and SAF-XJ 75-140 on LS diffs. Once it gets some temp and RPM I wouldn't think twice about a 75-140. But I don't think you can go wrong with what the manufacturer recommends.

[az3579]

BMW recommended SAF-XO 75W90 on open diffs and SAF-XJ 75-140 on LS diffs. Once it gets some temp and RPM I wouldn't think twice about a 75-140. But I don't think you can go wrong with what the manufacturer recommends.

Keep in mind BMW's recommendation for a limited slip applies to their limited slip. As I'm sure most of us with LSDs don't have a BMW one, it's important to keep in mind to always use what the manufacturer of the diff recommends for their product. :)

[GeorgeH]

Keep in mind BMW's recommendation for a limited slip applies to their limited slip. As I'm sure most of us with LSDs don't have a BMW one, it's important to keep in mind to always use what the manufacturer of the diff recommends for their product. :)

Yes this is what I meant, you said it better though. :)