Quote:
Originally Posted by F87source
Nope, I meant exactly what I typed saf- xj +FM. All LSD's need friction modifiers for the clutch packs to engage and disengage properly, without it the diff wouldn't work properly and with incorrect amounts it also wouldn't work properly, and in both cases the clutches would create alot more noise and wear excessively. The only difference from one diff to another is the amount of friction modifiers (FM) required, and the e series required a booster compared to the F series hence the + FM on the oil for the E series diffs.
https://www.fcpeuro.com/products/bmw...rs-83222282583
As far as I know for open difs they don't need friction modifiers at all, because they don't have the clutch packs that need to engage and disengage to control slip. So saf-xo is just standard gear oil. That would be really bad for an LSD in creating excessive wear over time. If you had tracked it I would be certain your diff wouldn't have survived, since track conditions require the LSD to function constantly as you transition from corner to corner and accelerate, also the diff would get insanely hot which doesn't help with wear either.
But yeah you're not the first person I've seen who had saf-xo put in their diff. I just can't believe how incompetent some dealerships are - which is why I check all service sheets and part numbers before I leave the lot. |
XJ comes with the FMs - which is why it's for LSDs?