Loud clatter when starting hot engine

[WRe]

Hi,
everything works fine with my late 280SL with automatic transmission, except when I start it hot.
When the motor is hot and it stands for half an hour there is a loud clatter from underneath for a few seconds (transmission in P). It disappears immediately when increasing the revs.
I checked all possible loose things but couldn't find anything. It seems to come from the driveshaft tunnel.
Any ideas?
...WRe

[Rick]

This is an issue that could be anything.   A loose alternator bracket or muffler to a bad torque converter or loose rods, etc.   We would only be guessing.  I suggest that this be looked at on a stand with a person who can identify the source.

[WRe]

Hi,
I checked the flex plate and bolts of the torque converter, everything ok.
Then I replaced the transmission mount (rear engine mount; part no. MB A1202230412 or Meyle  0140220010) and it's gone but I coudn't see any damage of the old one.
We will see what will happen next.
...WRe

[ejboyd5]

Timing chain.