I have a 79 Galaxie 17' V-hull w/120 Mercruiser (pre Alpha) . While out playing around yesterday , the freshly rebuilt outdrive (60 hrs)just quit driving outa the blue and all at once at 3800rpm. An odor similar to a burnt clutch (overheated brakes)was present . I brought it home and checked the gear oil and it seemed full and fine w/no metal shavings nor water, although it was black and smells like old oil but I assume this is normal. When cranking the engine a grinding sound is coming from the bellhousing area and gets much worse when the engine is fired and then comes and goes away . It will go in/out of gear but will not take the presure to move the boat . What is the best way to trouble shoot this problem so I can find the issue w/out dissasembling the complete unit .