Just as a follow up I have been running the Mobil 1 75w-140 with the LS additive in it and have had no troubles or chattering or grinding out of the diff. Cost 40 bucks for two containers.
**Follow up, after 500 miles the diff started to chatter bad on right hand turns so I went back to the FM boosted bmw fluid and within 20 miles the noise was gone. I know other guys running alternate fluids without issues but it dod not work out for me**
Electronics Junkie, Engine Builder.
Last edited by kawasaki00; 09-24-2013 at 08:33 AM.