Now that I have all the time to work on my car this winter, I want to actually do a tranny fluid drain and refil with filter repacement. I have taken my car to the shops for this job but now I want to do the job for experience. How shall I tackle this job for my 420SEL. Any special toos that I will need? And is it necessary that I use Mercedes Tranny Fluid or can I use any othehr fluid that is compatible?