Based on the analysis just posted of M1 75w90 in a 540i, I think a 140wt may be worth at least a try. At least trying a higher end gear oil like Red Line 75w90. But if the TSB says 140wt, that could be why they saw high wear...
I'd recommend Red Line 80w140 from our site sponsor. Or the 75w140NS and add the FM separately.
I'd recommend Red Line 80w140 from our site sponsor. Or the 75w140NS and add the FM separately.