Torn65

I have a 1998 C280 with 203000 kms on it and need some help with the following issues 1. Car has a small knock coming from the transmission/tail shaft area under light acceleration after backing off. I suspect the slip joint in the drive shaft as the rubber universal joints are in good condition. Does this model have slip joint issues? 2. Drivers seat back has a small amount of give and gives a slight knock as well. I suspect something is worn in the seat back adjuster. Once again does this model have seat adjuster issues. 3. The steering column appears to has a noise coming from the lower steering column to steering box joint. Are these joints also a known problem area? I know it sounds like I am being fussy on issues with a car that's nearly twenty years old but I still enjoy driving it and think it looks better than most newer models. Any constructive advice gratefully accepted. Kind regards Torn1965