[WIP] D-N-R-P + 4-Speed gearbox

[Scoar Sonander]

I had an idea. 

In most cars, there is not just one single gearbox, but 2. The one for speeds, and the one for drive, neutral, reverse and park. In Lego sets, both gearboxes are usually captured. But also usually the park is left out of the second gearbox. I'm here to change that. After a couple ideas of racking my brains and to many hours to count on Stud.io, I have found a solution that adds park to you car. The idea is that there are two gearboxes in the car, behind the seats and in front of the rear axle. One controls drive, neutral, reverse and park. It also controls if the second gearbox is used or not. Only in drive does it direct the power from the rear axle through the 4-Speed gearbox next to it. Here it is:

This showcases drive mode, where the power is directed to the 4-Speed gearbox on the side.

Park...

Neutral...

And reverse. 

Thanks for reading, and everybody is free to use this concept in their builds! 

Edited August 12, 2021 by Scoar Sonander

[RazzPinazzo]

Click "share" below the picture on flickr, copy link and paste here (press enter after link and it turn into pic

[Scoar Sonander]

Thanks! 

[2GodBDGlory]

Good job!

I always like seeing new gearbox designs, and PRND is definitely something that is often left out of MOCs.

[1963maniac]

This is great! Do you have any photos of the underside to share? I have never seen a design with park which controls whether it moves or not.

[Jurss]

Geaorbox is OK, but You know, in real manual gearboxes as P always 1st gear is used, there is no specific P position.

[Scoar Sonander]

2 hours ago, 1963maniac said:

This is great! Do you have any photos of the underside to share? I have never seen a design with park which controls whether it moves or not.

I'm glad you like it. By the way, the input is the 20-tooth gear connected to the P-N-D-R gearbox.

 Here's a pic of the underside, 4-speed on the bottom and P-N-D-R on the top (completed version, mind you):

And here's a picture from the top of the full gearbox, 4-Speed on the top and P-N-D-R on the bottom:

Of course it still needs the "slim treatment" if it's to actually fit anywhere, because at the moment the dimensions are a pain in the megablocks.

[Celeri]

I never really thought of a "park" position in a LEGO car's gearbox, but it definitely makes sense: well done!

[2GodBDGlory]

5 hours ago, Jurss said:

Geaorbox is OK, but You know, in real manual gearboxes as P always 1st gear is used, there is no specific P position.

Yes, but automatic cars, of course, have to have a unique park control, and Lego sequential gearboxes are probably nearest to a real-world sequential automatic gearbox. Real torque-converter automatics use a separate parking pawl for the park, housed inside the transmission, but I don't know about real sequential automatics. Perhaps they just use first gear like a manual? Either way, this is a nice solution. I also built an interesting PRND gearbox based on sliding gears for my 1:7 Bugatti Chiron; perhaps I should post it on here sometime!

EDIT: I have now posted my design:

 

Edited August 13, 2021 by 2GodBDGlory

[Johnny1360]

Very neat idea, thinking outside the box but I always thought the term park was reserved for automatic transmissions. Mostly because when the engine is not powering the hydraulics every gear essentially becomes neutral. Where as a manual gearbox uses the non-running engines compression as a brake of sort, or park if you will. 

I suppose since LEGO fake engines have no compression this could be handy to keep your model from unexpectedly rolling away, down hill or something, other than that it doesn't really have a use, still it is a cool concept.

Now all we need is an automatic or hydraulic transmission to put it in.

[Scoar Sonander]

6 hours ago, Johnny1360 said:

 

 Now all we need is an automatic or hydraulic transmission to put it in.

Yes indeed 

[Scoar Sonander]

After some rebuilding and redesigning I finished the gearbox and created some instructions for it. If anybody wants them, PM me. The reason for this is I lost the Stud.io file...  so I can't upload it to rebrickable, and only send you guys the instructions per email.

Edited August 16, 2021 by Scoar Sonander

[Meatman]

Lego sets most likely don't use a "park" feature because no doubt they will have complaints that the user broke something.

[Hrafn]

8 hours ago, Scoar Sonander said:

After some rebuilding and redesigning I finished the gearbox 

Can you post a few photos of it?

[2GodBDGlory]

On 8/16/2021 at 1:48 PM, Meatman said:

Lego sets most likely don't use a "park" feature because no doubt they will have complaints that the user broke something.

The Volvo hauler did actually have a park gear of sorts, as when in the dumping gear, it locked the wheels to a linear clutch, stopping the vehicle. The clutch did prevent breakage as well.