diff fluid for e60 (non m)

[tonton 3]

hi guys, just wanted a peace of mind. i've been looking everywhere regarding this and some say 75w-140 is ok. but some say it's not and recommends 75w-90. 

i took my car in to bmworkshop and they put in castrol syntrax lsd 75w-140 in it, but burger in the north shore recommends 75w-90

question is, is there any negative effects with 140 weight oil in the diff? 

i did feel like the 140 weight oil feels a little bit.. bogged down compared to my old fluid which has probably turned into mush now (car has 145000ks, diff fluid never been done). it could just be my inaccurate ass dyno but idk

 

p:s, it's already done and dusted with 75w-140 in my diff. just looking for a definite answer so i can finally go to bed in peace haha