There are a couple of screws on the motor itself that allow it to come out of the housing. It's been >18 months since I've had mine apart, so I don't remember the specifics. The whole worm gear part will pull out of the motor "can". You'll see the important parts inside.

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]