Originally Posted by tns1

The SRT400 is similar to the other SRT models, but the cable door is different. It isn't a round plug, and it isn't held on with a screw. The large rectangular door fits so well it looks like just another part of the housing. Unlike the SRT600 model shown here: www.youtube.com/watch?v=YmOVOc-iLcY, the cable door must be removed before the shift barrel can be separated from the housing. Near the cable tension adjuster there is a shallow slot that looks like a pry spot for a screwdriver. Instead of prying, push a thin blade into the seam in this slot. With a little twist, the door will slide open easily. There is no need to remove the rubber grips. The cable routing of the rear derailer is the same as the SRT600. The front derailler is simpler.