While changing my 2 rear wheel shafts because the boots were torn i noticed that it looked like a leak might have been up front of the differential by the drive shaft. It may just be from the boots being torn. Can it leak from there. It was dark already and i wasn't able to see well so i'll have to look better tomorrow. I posted on the forum last week that there was a repetative knock in the back of a car i just bought (240D 1984). It sped up as i went faster,and slowed to a stop when i let off the gas. I was advised to change the old axles which was a good idea. I thought while i was there I'd get a knowledgeable opinion or expert advise in case i can save steps. Hopefully someone will tell me it doesn't leak from there. RAY M