What are the symptoms of bad axles?

[olsaltybastard]

I've got an '83 300D with 133,000 miles and a pretty serious issue. I have a very loud noise coming from what seems to be the rear of the car; like a machine gun only not as loud. As I slow down, the clanging slows down also. I replaced both rear sway bar endlinks hoping for a low dollar fix, but it didn't do the trick. There is nothing that is obvious when underneath the car. I took it to the mechanic and he couldn't find anything wrong from a visual inspection. I have taken him for a ride on two separate occasions, and OF COURSE THE NOISE WENT AWAY!!!!!! It comes and it goes. When it makes the noise, it does this until I come to a complete stop and then it goes away for a while. I'm in a pretty bad mood right now, so I would certainly appreciate some input from calmer heads. Any ideas on what this may be? I don't want to spend several hundred dollars on axles only to have the problem emerge when I finish. The axles boot closest to the differential is torn; the oil is in my driveway.