When you pop the linkages apart, be certain to clean the balls and re-lube the sockets. FSM may suggest ATF, but I use white lithium grease per a conversation with a MB parts guy (Tom Hanson at Caliber Motors).

Be prepared to get physical with the linkages. The first time I worked on mine, they were really stuck -- I don't think they had been lubricated in a LOOOONG time. You don't want to bend the rods, but you do need to apply enough upward pressure so that the wire spring clip will relax around the ball and allow the two pieces to seperate.

My 300SD has an access panel inside the engine compartment on the passenger-side that has connections to the starter motor wiring. It is really easy to clip a switch in here and use the starter to "bump" the motor around to achieve the correct cam placement for valve adjustment. The "Remote starter switch" is available at many stores, including Sears and Pep Boys. I don't know if the 300D has this panel available or not.