Catharpin 10 Posted March 19, 2009 Hi, I have a 2001 big bear 400 4x4 and was wondering what kinds of fluids I need to use. The guy I bought it from said it had all synthetic so I would like to stick with that. For the engine oil can I just used mobil 1 or similar synthetic? What about the differentials? Thanks! -Brian Share this post Link to post Share on other sites Like what you are reading? Please help us by sharing this content.