This model is base on the Allison 1000 automatic transmission. Is not an exact replica, but the basic design and functionality is the same. The most significant difference from the real transmission is the C1 and C2 clutches that I design to work with 3D printed parts and for easy engagement.

Was made with Blender, and I have very little knowledge on how to use it so the parts don't look pretty on the images, but I check on Cura that everything is solid and ready for printing.

Assembly video: https://www.youtube.com/watch?v=vvhICaIRjOY

Gear ratios:

1st: 3.20

2nd: 1.86

3rd: 1.43

4th: 1

5th: 0.70

6th: 0.60

R: 4.41

The default size is as small as I could (the case is 12.5 cm long), and I am not sure if is too small so I suggest printing the P1 planet gear first to see if is large enough to have enough detail. That is the smallest part of this model so if is successful, then everything else should be fine.

I made the lower part of the case quite big so there is room for optionally put solenoids to engage all the clutches and even a parking pawl. If you are interested on this you should print all the "Solenoid Version" parts. This will allow you to engage the clutches more easily with switches, or even change gears automatically with something like Arduino.

I don't have a 3D printer so I would appreciate any feedback from people that printed one to improve the model. Still, I check all parts on Cura to make sure all is ready to print, except the orientation. You will have to rotate some parts to print it in the optimum way to have the least overhanging.

Instructions

You need:

• 1mm rod
• 3mm rod
• 21 self threading screws to fit on a 1mm diameter holes
• 2 self threading screws to fit on a 2mm diameter hole.
• Several washers/spacers for the 1mm and 3mm rod.
• 1 snap ring or E-clip for the 3mm rod.
• 2 bearings 608ZZ - 8x22x7mm (inside diameter x outside diameter x width)

The file names are self-explanatory. Print the number of times mention on the file name and assemble like shown on the video.

Use the 3mm rod for the center of the transmission and for the clutch forks.

The 1mm rod is to hold the planet gears to the carrier.

I recommend putting washers in all planet gears and each side of the 3mm center rod.

As I show on the video, you need to put a snap ring or E-clip after the C2 clutch to hold all the planetary gear sets together. To do this you need to create a notch on the rod.

I recommend begin the assemble from output to input, like on the video.

P1, P2 and P3 are the names of the planetary gear set, numbered from input to output. If you don't know the name of the parts of a planetary gear set, here it is:

• Sun gear: the gear in the middle
• Ring gear: the big gear that covers all the gears
• Planet gears: the gears that go between the sun gear and the ring gear
• Carrier: the part that holds the planet gears

The default version is design so the user can engage the clutches manually using the 2 rods that are at the ends to engage C1 and C2, and the 3 buttons on the side to engage C3, C4 and C5. Just keep at hand the clutch application chart so you know which clutches you need to apply for each gear. For this version you don't need to print the files that start with "Solenoid_Version".

Solenoid Version:
I made an optional case and some extra parts so you can add solenoids to engage all the clutches electrically. You need 6 push/pull solenoids with a body size of 30x15x15x30mm (LWT). I recommend this solenoid:

• DC 12V 1A 10mm Stroke Push Pull Type Open Frame Solenoid Electromagnet
  http://www.amazon.com/10mm-Stroke-Frame-Solenoid-Electromagnet/dp/B00HR8H38A/ref=pd_sim_sbs_328_1?ie=UTF8&dpID=41Cc6i7YiKL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=0GGZ30M84BCFJAXY1ASB

If you want to build the solenoid version, don't print the following files:

• Case_x1.stl
• Clutch_Button_x3.stl
• Clutch_Fork_x2.stl

Those files are only for the basic version that uses mechanical buttons to engage the clutches.