The Instructions for rolling the Car back and fort with the full weight of the Car and wheels on the Ground to center the Drive Shaft before tightening the Collar Nut is in one Factory Service Manuals of I think it was a W116 (I think?); which has the same Drive Shaft set-up.
Anyway I read the instructions on this Forum.

I have not taken the time to search the W123 Paper Manual I have but I know there is more info in the Paper Manual as I have seen stuff there that is missing from the English Language CD Manual Set.
Also it is know that there is mistakes in translation and omissions in the Factory Service Manual CD.

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84 300D, 82 Volvo 244Gl Diesel