Summary

This modification splits the extruder assembly into two parts.

Advantages:
easier assembly and disassembly
less loose parts
remove minor clogs without removing your motors
preserves the threads of your nema motors....which were never designed to be remounted over and over in the first place!!!!!

Instructions

Parts:
4 - M3 x 25mm Socket Cap Screws
4 - M3 x 12mm Socket Cap Screws
4 - M3 nuts
4 - #4 x 5/8" Sheet Metal Screw
2 - 3 pin connectors (pc fan)

print part; fill - 15%, layer - .2, shell - 2, no raft, use supports
disassemble extruder assembly, remove heat sink
using a drill press, widen the existing holes with a 7/32" drill bit
!IMPORTANT! make sure you get the hole "dead on" or your heat sink will mount crooked! These are clearance holes for the heads of the socket cap screws.....check to make sure that holes clear the heads, but still have a close fit; it cannot be loose!!! (see pics) make sure you deburr the holes
set your fans up with some kind of connectors. I used a 3-pin fan connector (see pics) similar to ones used on pc fans.....you'll want to keep these small; their is very little clearance, especially when the extruder assembly moves to the front of the bot. You can mod your existing fans or buy new 40mm fans with connectors already on them. Obviously you will have to splice in a connector to the power fan of the bot as well. Label these L and R.
mount the fans to the heat sinks using sheet metal screws (see pics) these should have a tight fit....be careful to not over-tighten!!!!
mount the extruder motors using the 4 - M3 x 25mm screws
remove supports from part and press the M3 nuts into the recesses.....you can thread the screws from the other side to help with this
press the part into the carriage....tabs should drop right into place.....if the part doesn't sit flat you may want to scale and reprint
drop fan assemblies into place, mount with M3 x 12mm screws
connect fans, your all done!

Rep 2x 2-Part Extruder Assembly