If it was anything like mine, you'll be lucky to have much oil in there at all!!
I run CoreRC 400cst Front and 350cst Rear (40f & 35r), I find it works well on the track, however if im bashing i do add another large spacer to the rear's. As stated before it is trial and error, find what your more comfortable, that goes for the Diff oils too, most people go for Medium Thick Thin for example mine are CoreRC 5000cst Front, 7000cst Middle, 3000 cst Rear.
This might help, something Deafty posted a while ago!!