I drained the black glop (literally!) out of the differential. I've never seen such goopy stuff. The first mound of it that fell out into the drain pan, before I got the ooze going through the hole to the inside, stayed there during the entire operation. It was like black runny peanut butter. I let it drain for half an hour or so, then put the plug back in and filled it with diesel. Then I ran the car in gear for a minute or two and drained it again. The diesel came out black, but the glop in the bottom was hardly touched. So I got out the oil sucker and slurped it all up. Then I repeated the diesel sluicing, and then sucked it out once more. I put in 1.5 quarts of gear oil and took it for a test drive.
Still noisy. Crap. The differential that's in there bears a 115 part number, so I'm sure that either of the differentials I have squirreled away will work. (I think I got one from a 123 and one from a 115.) The one that I put on the parts car (so it would roll) has the same bolt-based attachment for the half-shafts, so that's the one I guess I'm going to use. I think it came off of a 240D, though it is on a 300D right now. More work to liberate it first, but what are you going to do? -- Jim
