Hi, I'm Joe Parr and have been a club member for a few years now. I have a 2003 530i that i bought in 2006 with 10,400 miles. It now has 92,000 miles. I have just had the cooling system replaced to prevent future problems and now I am going to change the rear differential oil. My indie BMW shop guy says they use Valvoline 75w145 in all applications. The Old School Maintenane guide and BMW recommend 75w90. Is it okay to use the 75w145?