Quite right Newboy707, and that, of course applies to all the NG family.
The trick is to make sure the little door is closed when you are flying normal ops, or as was mentioned, the gear won't retract after takeoff!
It's all to do with making sure the hydraulic fluid is able to flow during a manual extension cycle, without causing a hydraulic lock.
The door must be closed at all times except as necessary to manually extend the gear.
Cheers FD
