Maybe he's talking about the special "bolt" needed to center the gearbox and what he's actually saying is that he needs this to center it before he can feel comfortable that the alignment is done properly?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280