RE: LEAKING DIFFS
6 screws, leads me to think you have the spider diff in there, if so ignore the last 2 posts as they are irrelevant, SPIDERS HAVE O-RINGS, Dab the head of each screw into some RTV (silicone) sealant before you slot it in, then do each screw up in the diametrically oppossed style, sit the diff on one end so that the heads are at the top and allow it to dry.