If you are referring to splitting the gearbox and removing the top casing, then you need to lift the casing to clear the dowels and rotate it around 20deg counter clockwise or there abouts, (I think it's counter clockwise), it will also require some tilting, (maybe 5deg from horizontal), to get it to clear the selector mechanisms. You get pretty good at finding the sweet spot once you've find it first time.
If you lift it straight up and proceed to lever and bash things, be prepared to wreck things.
If a bearing has dropped out, this is quite normal, as the top bearing race from the main input shafts quite often drop out. You can stop that from happening by removing the end plate which is used to shim the tapered roller bearings, (6 bolts), and remove the top race and shims for safekeeping.