Made DDeGonge888's extruder, once I put it on my TwoUp with other upgrades I found that I was unable to clean the teeth on the gear if I was unfortunate enough to have set the wrong tension. His extruder has been working great, but when I opened it up I found I had tons of plastic in the gear teeth. I have some dental picks for cleaning them but they are not accessible with his design. This has fixed it for me. Please forgive the imperfect fit in the pics, I had made some setting adjustments to the steppers that need to be corrected. But, even like this, it is working great. I was also able to adjust the positioning of the gear with relation to the filament and idler bearing through this opening.

4/11/15 update.
Just ordered an E3Dv6 for this thing and realized I wanted the same thing for that extruder. Edited it, sealed it with netfab, still imports to Repetier saying it's not manifold but it prints fine. Will know in a few days when the hot end arrives if it works just as well.