Neither the FSM, nor a search of the forum turned up what I needed, so please help.

I need explicit instructions on re installing the cable for the sliding roof for my '82 300SD. It is not of the rear lifting variety.
The spring clip that retains the outer sleeve moved while I had the cable out, and it is not obvious how it is supposed to be installed. I believe it is to retain the flange on the tube to the cross header. I cannot make it lie in a way to do this. Any pictures in the FSM are too dark to be of any help.
If I understand how this is supposed to work---it seems that the front end of the cable connects to nothing other than the sliding tube. this is done by a small spring clip that connects the two at the extreme forward end. What is the purpose and proper orientation of the black plastic piece that slides over the tube?
The clutch has begun to slip as I open the roof ( loud ratcheting noise). I know there is an adjustment, but should I? How do I determine if I need to adjust the clutch, or look elsewhere for the root problem?
Thanks for your help.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags