Rat Rod Gearbox: Quite a few people asked how this works, so here it is. As you can see it's pretty simple. This is, I think, the smallest working Lego gearbox possible.
About this creation
I've been getting questions on how the gearbox in my Rat Rod works, so here you go! Below are pictures of its gearbox with the cover removed. It's as compact as I could make it, so it'll fit in most large scale vehicles. I've used it in supercars, trucks and the Rod you see on this page.
It isn't strictly an automatic (it can't change gear by itself), but it does have Forward, Neutral and Reverse (or Drive, Park and Reverse if you like) which really work.
Remember this is just one part of the drivetrain, it works best when combined with an engine and differential.
Here you can see the input shaft coming from the right-hand side of the picture to the dark grey cogs, and the output shaft next to it with the light grey cogs leaving to the left-hand side of the picture.
There are 2 cogs on the left and 3 on the right (although you can only see 2 in this picture).
Remember where your driver would sit; that grey thing in the middle on the input shaft is where the gearstick slots into, so make sure itís going to be central in the cockpit and in the right place for a driverís arms. The dark grey cogs freewheel until this brick locks into one of them, engaging that set of gears.
If you don't have this piece don't worry; you can create a working gearbox without it. Before I had the gearbox part I managed to make a working autobox, it was just a bit messier!
This picture shows the gears connecting.
-The 3 cogs on the right are; medium, medium, small.
-The 2 cogs on the left are; medium, large.
It's this odd and even number of cogs which changes the direction of the output shaft, thereby giving the vehicle two directions whilst the engine only turns in one direction.
This arrangement means Reverse is geared twice as low as Drive, which is more realistic. Obviously if your car has a different number of cogs between the gearbox and differential you will have to turn the gearbox around 180 degrees, or Reverse would become Drive and Drive become Reverse.
This picture shows the layout of the vehicle. The engine is in the front, the gearbox in the middle and the driven wheels at the back, making it a nice linear drivetrain. Putting this gearbox in a mid-engined car is fairly straightforward; the input and output shaft just have to stick out of the same side of the gearbox. The same would apply to front-wheel-drive, but that gets complicated!
I've sent a file out to a few people with arrows on the pictures to make them easier to understand. Contact me if you'd like it. When building your gearbox I find it easier to make it out of the car, but on a solid baseplate, as this helps when aligning all the shafts and cogs.
Quoting vwpint vwpint
That doesn't work. First gear will move the car straight and the other backwards.(sorry about my bad english)
Correct, that is what the gearbox is supposed to do. It means the engine only turns one direction, but the car can travel in two directions (forwards and backwards, plus neutral). Hope that makes sense, I appreciate English isn't your first language!
very clever idea, and it's also very compact. i checked out your home page, and it's refreshing to see someone who's polite on the internet, especially since this morning i was looking at someone elses homepage and their mocs, and that person was terribly rude. thanks :)
I like it
February 15, 2010
I like it
February 14, 2010
ive tried to make it from the photos you have hear but i cant seem to get it, could you help? heres my email: firstname.lastname@example.org
hey. I built the gaerbox but the axle ceeps on goin in one direction. please send pictures of the entire drivetrain and gearbox connected so i can see what i made wrong. send me pics at email@example.com
Hey Ape, I was just wondering if you would be a judge for Exclusively Pickups contest if you aren't going to join it, because Matthew Harned and I will be contestants, and it wouldn't be fair if we were judging our own creations against other peoples. I'd appreciate it.
Thanks for the nice comment.....I'll make it on are new PC and give you the building instucitions but....I can not make it in reall life because i do not have the window i used for a grill but you may have the plan to make it and buy it.
I vaguely remember writing that comment, but not here. I have never seen this page before, and I do not know why you are unable to click on my name. This is clearly just some kind of error in the system. Please delete the comment.
Thx man! I really consider good builders opinions.. about the parts.. I've never ordered even a brick.. but I have a lot of FXX sets using them in my creations.. and about your note you really hit a very important point about the reviews and rating thing.. I'll do by your advice from now on(well i'll try ;)) thx buddy :)
Wow. I've seen a few creations that have had gearboxes and I still don't fully understand how these Lego versions work but this helps a little. Nice work! Thanks for the review too! I had a lot of fun with that build. There were a lot of creative entries in that contest and I'm glad I was able to post my own. I spent most of my time on the minibus. Its a simple build, but there were so many different ways to do it, I had trouble setteling on just one. Maybe I'll make another bus or two later on. Sorry for the long comment, I have a bad habit of leaving short stories in peoples comment boxes :-/ Peace - Patrick
oh um..i dont know if i told you this but...i..uh...i didnt use your design...used...some other guy's.( i will still give you credit ) o hand its four wide with now gears sticking out and its only 2 bricks and 1 plates tall.