Traxxas TRX-1 / TRX-3 / TCP Gear Box Housing

thingiverse

Traxxas TRX-1/TRX-3/TCP Transmission Case/Gear Box Housing Set (2791). This case set is designed to work with the original inner gears for the TRX-1/TRX-3/TCP buggies (2.14 FDR). This is based on modeling/dimensions of a TRX-3 transmission. This design has been modified versus the original to make it a bit more printer friendly. It also has a bit more clearance around the gears to allow for some printing variation/tolerancing. It is also not fully sealed at the base. The wall thickness in this area was getting down to ~0.4 mm and I did not feel this could be reliably printed. Most of the Magnum 272 equipped Traxxas transmissions from this area were open at the bottom, so I took that approach to this design. This cleaned this area up and allowed for easier printing. If this is a concern, place some thin vinyl tape over this opening and this will be more than enough to keep debris out. Post-printing requires tapping of holes with a M3 tap. Light filing/sanding may be required to allow for a nice fit to the rear bulkhead and fit between the rear arm hinge mounts. Similarly, ensure that there is no stringing left in the inside to prevent gear damage. NOTE: I have printed an earlier revision of this set and it was assessed for fit of gears/bearings/etc. Extrusion/dimensional control is more critical for these to fit properly. There is allowance for tolerance variation, but fit of the bearings and the overlap will require some level of understanding control of your printer tolerances (i.e., need to be within 5% of true dimensions/line width). I would print this with the outer face against the build plate. This allows for clean internal surfaces with good dimensional control. This design is based on the ideal pitch diameters for the gears. I may add some additional backlash, but I do not see if changing significantly.