The nut should be tight. there is a dust boot that covers the splines. yours looks petrified.
The U-joint should be snug w/o any loosness in it. they do become notchy when bending them. I have seen this on lots of MB.

If it is wobbling around, and you see it at the front flex disc, then might be a good idea to replace it also, along with the center support bearing.

If you see and feel the loosness in the u-joint, then it is time to have it replaced. they are staked in, and are not a DIY job.

I had mine replaced on the 85 300D. the shop replaced the center support bearing, and replaced the u-joint with a greaseable one that is used in a lot of Fords. YEP. got a Ford part on the ole MB.

they charged me $256.00.

Here is a shop that does MB drivelines in Portland. not all shops can do them.

Driveline Service - Mercedes Driveshafts


Having the car upn a lift with the driveline turning, you would be in a heap of hurt if it should grab a piece of clothing, hair, neck tie etc...;
Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works