dont sweat it - the D shaft has factory markings that you need to align back as shown in the picture. Whilst you have it disassembled - get some high moly content grease - or the paste BMW motorcycles use on their rear wheel spline drive. Its a moly paste made by Dow. And is the same thing MB specced for lubricating the middle splines and bushings on the end of the D/shaft with. Both bushing ends take 6gms of this paste and the splines take a slather of it.

This special paste is also available at "level headed" honda motorcycle dealers or specialty motorcycle repair shops. Its light gray in colour and the only way it gets off your clothing is putting them in the trash.

Replace that little boot - its a 3 or 4 dollar part and is made from plastic now.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)