This video will show you how to dismantle and access the trigger assembly of the M4177:
It's a great tutuorial, however, this guy is clearly trying to improve his trigger pull, but he doesn't seem to understand that greasing alone will not accomplish that. It may slightly improve the feel of the trigger and stop any squeeking, but it won't lighten the pull at all.
There is a lot of travel on the M4177 trigger and Crosman puts a really high tension spring in there which makes for a very heavy trigger pull. Fortunately, there's a simple do-it-yourself mod which will fix this. Take the trigger spring (not the sear spring), and bend the straight tine on it to about a 35 degree angle in the same direction that the coil is turning. You will need two sets of pliers. I used needle nose and channel locks.
Here is another video with more info on tuning the trigger: