intermittent "clanking" noise from auto trans w123

[yellowbenz]

Hello all,

I have noticed an intermittent clanking, metallic noise that seems to be coming from the auto trans on my new to me 1978 300D (157000 miles). Has the often described hard/firm shift from 2-3. Fluid is pink and proper level at operating temp. In addition to this intermittent (every 5-10 seconds) there seems to be a rubbing or squeak from the trans that is noticeable at idle only.
I've done some searches and will get out my mity vac to trouble shoot the shifting issues but I'm looking for some guidance on the noises. If I can figure it out I'm going to try and get a short video with sound or a sound recording and post it. Thanks for any and all help.

Kevin
1979 240D manual
1978 300D