300D Nasty noise
 

While driving in to work this morning my 83 300D sedan started to make a pretty nasty noise. Initially I thought it was the exhaust system as it had that kind of quality to it. I'm not so sure now. I don't hear normally, I have implants, so it's hard for me to tell exactly what all I am hearing. The noise seemed to get worse when I turned the car. My concern/question is am I possibly hearing the flex discs getting ready to fail? Is there some warning noises before these total themselves? The car's not shuddering or anything like that. The noise does seem to be speed related as opposed to engine speed related but of that I am not 100 % sure. Any advise as to how to check the flex discs is appreciated.
Thanks much.

Visual inspection of the flex disks is the first step. If they aren't shredded, go to the next step...use a long screwdriver or pry between the driving and driven sides of the disk. If you apply pressure and there and the rubber looks cracked or deterioriated, replace them.

While under the car, inspect the center support on the driveshaft. Bad or deterioiated rubber in the mount can make weird vibrations/sounds at lower speeds. Check the rear engine mount too.

I'm going to do a crawl and pry over the long weekend. When I was driving it home last night, it really started to make a LOT of noise. Riding slowly in traffic next to a Jersey barrier, I lowered the psss window to see what all I could hear. It sure sounded like some engine related noise, the exhaust in particular. I guess diesels, turbo-diesels must sound a lot different than regular old gassers with busted pipes I was all happy that I thought I found the problem, then, as I got close to home it just stopped. All went back to normal noise, wife couldn't hear anything out of the ordinary from under the car. Since the car ran fine power-wise and all, I don;t think it's any sort of flapping wastegate or anything like that. All I can figure is there's a break in the pipes, probably at one of the flanges, that will open and close up by itself. Very weird old beast.