I have an S awd 09 rogue with a cvt transmission.
After around 3000 km my engine start to rumble (kinda shaking... I'm french so you'll have to forget my english ;-))and make a noise. After i speed up a little it would stop the rumble and the noise. I had also noticed in my drive way that my car was leaking.
Went to the dealership, he told me he had to change the seals on my transmission. After he did it, all the troubles were gone. By the way, when checking my oil, the mechanic told me that my engine should always be on.

Hope that helped!