Hi I think the general rule is less grip lower weight oil, high grip higher weiht oil. I wouldn't worry too much about your diffs looking underfilled, mine do when i change the oil and if they had 20wt/10wt this will look a bit like light grease when you come to change the oil.
It's a personal think but I have my base set up 12.5wt/7wt going to 15wt/10wt high grip or 5wt/10wt low grip.
Hope this help, I'm sure others will chip in with some better info.
Sam
|