You can't. you have to split the case, if you have the engine out already its no big deal. You will see how it all goes, and why do a job half way, once you split the case replace them all(front & Rear). Make sure you use a torque wrench when puting them all back together. Once you get it apart you will see its not has hard as you think. Anorobilc sealer on the case when you join the halves back together and then torque. Good Luck Have fun. New Jet Ski Parts and Used Jetski Parts - Jetskiparts.com will have a breakdown of the case for you to see.