How do you build a 2 speed automatic transmission?

[LegoBuilder919]

Hello everybody. I am trying to put in a 2 speed automatic transmission, to a large MOC. I already have a 4 speed manual transmission, but it is hard to reach. I want something that when it goes up hills, it can automatically give more torque with out me having to shift it. Does anybody know how to do this? PDF instructions would be helpful. Thank you, LegoBuilder919

 

[suffocation]

I think Technic Brick Power built something like that. Check his videos here: https://www.youtube.com/c/TechnicBrickPower/videos

Also see Sariel's 4-speed automatic gearbox:

 

[LegoBuilder919]

@suffocation Thank you for responding, but not really what I am looking for. That is more of a main gearbox (which I already have). I am looking for just a simple 2-speed addition that goes from a 1:1 ratio to something lower. Thanks, LegoBuilder919

[2GodBDGlory]

My personal favorite design is one I came up with a while back, using the planetary hub part. You can see it in this topic (it is improved towards the bottom of the thread)

It is also more of a main gearbox as well, and it's 5.5x difference in speeds is likely a little much, but it is reasonably compact, in my opinion. YouTube seems to have dozens of other designs, too, though I worry about durability with many of them.

 

[LegoBuilder919]

19 minutes ago, 2GodBDGlory said:

My personal favorite design is one I came up with a while back, using the planetary hub part. You can see it in this topic (it is improved towards the bottom of the thread)

It is also more of a main gearbox as well, and it's 5.5x difference in speeds is likely a little much, but it is reasonably compact, in my opinion. YouTube seems to have dozens of other designs, too, though I worry about durability with many of them.

 

This would most likely work, but I don't have the parts necessary to build this, is there any way to build this without the hub? Or can I replace the hub with something? Thanks, LegoBuilder919

[992bricks]

Some designs that I find really useful are the ones using a differential, and if you want an example, look up 2-speed automatic transmission on YouTube and they should come up.

 

[2GodBDGlory]

2 hours ago, LegoBuilder919 said:

This would most likely work, but I don't have the parts necessary to build this, is there any way to build this without the hub? Or can I replace the hub with something? Thanks, LegoBuilder919

The hub is pretty essential, unfortunately. It could theoretically be replaced, but it would become even more bulky, and much less reliable.

Also, have you considered adding a remote controlled 2-speed instead? This would be simpler, more efficient, and more reliable than any automatic I know of, though it would require an extra motor and is admittedly less cool.

[LegoBuilder919]

28 minutes ago, 2GodBDGlory said:

The hub is pretty essential, unfortunately. It could theoretically be replaced, but it would become even more bulky, and much less reliable.

Also, have you considered adding a remote controlled 2-speed instead? This would be simpler, more efficient, and more reliable than any automatic I know of, though it would require an extra motor and is admittedly less cool.

I have not considered a RC 2-speed, but I think it would be too big for the space I have.

 

@992bricks I will definitely look into that. Do you have any that stands out to you in particular?

Thanks again, LegoBuilder919

[2GodBDGlory]

4 minutes ago, LegoBuilder919 said:

I have not considered a RC 2-speed, but I think it would be too big for the space I have.

@992bricks

In my opinion, a two-speed shifted with an m-motor is likely to be as compact as any auto capable of the stresses involved in the climbing you mentioned, but I don't know what your space looks like in the model. I hope it turns out well!

[LegoBuilder919]

On 7/10/2021 at 7:10 PM, 2GodBDGlory said:

but I don't know what your space looks like in the model.

I can't send you a pic, but it is a 6x11x4 stud space (now that I think about it, that might be enough space), and the left over of where it is, will also end up being an engine mount. When I designed the MOC, I didn't plan on a 2 speed so it is not ideal.

Edited July 11, 2021 by LegoBuilder919

[992bricks]

@LegoBuilder919 This one is really nice, it is also very compact too; 

I would share my design, but Studio is not letting me export the instructions.

Edited July 12, 2021 by 992bricks