Hello all. Im working on my "new" 240D with 328K miles on it. It has a 4speed manual transmission. The manual says to use 10w20 oil. Ive never seen this weight before and I wonder if the new SM oil will be bad news in this unit. And for the diff it says to use 85w90..That should be easy to find but would there be any advantage to going with another weight in this high millage rear? It doesnt seem to me making any funky sounds. Thanks.