This is remix from Minimalistic Mk7 replacementhttp://www.thingiverse.com/thing:15718Advantage of this mod:1. Quick release/loading of filament, by pressing the lever to disengage the drive gear.2. Allow easy cleaning of drive gear (it is exposed). You can clean it even during mid-print.3. Smoother feed than the stock zen drive.Even though it will provide smooth filament feed, I don't think it will solve all your filament jam problem. For that, you need to look into your hotend.Should work with both the old & new drive gear.Check this post for details and build instructions:http://tinkeringinhk.blogspot.hk/2014/04/minimalistic-zen-replacement.html