Flex joint (W126) - inspection?

[86560SEL]

Hi all,

Now that my mom got a brand new SUV, I got my '88 300SEL back. It will be an extra car for me and I am trying to get it back up to par.

I need new ball joints and a LF wheel speed sensor for the ABS, but I THINK it may also be ready for a new flex disc joint (if I am calling that the right thing). I am thinking it is the thing that is round and has holes in it (universal joint on most other cars).

The reason I ask is that when the car is placed in reverse, sometimes you can hear a clunk, or when it shifts when slowing down, you can hear a click/ticking sound from under the car. I bought the car in 2007 and I know it has never been changed since we have owned it.

I didn't want to go by sound alone and have it replaced, so wondering if this sounds like that is causing the sound and if there is a way to check it?

Thanks!