[HELP] Gearbox and XL Motor Mount for Trial Truck

[Mechbuilds]

The front axle is the one with longer linkage. (the front axle is already done but not shown in picture)
The rear axle is the one with shorter linkage. 

I need a gearbox that'll gear it up a bit so it can rock crawl. 
The XL motor can be mounted either back on top of the rear axle which will cause problems on battery box fitment. 
OR the xl motor can be flipped to the front as long as it's not longer than the first black 2 long axle bushing after the U-joint on the front axle. (preferred so i can mount the battery box on top of the rear axle.)

Problem i have is figuring out what kind of gearbox to make that can fit in the middle and how to connect the linkages to the bottom of it. 


EDIT;

Front axle added:

Edited June 28, 2019 by Mechbuilds

[agrof]

Take a look at Madoca's Fj40, it has similar setup what you wish for - and of course it is brilliant:

https://photos.google.com/share/AF1QipMYFnh0FV07dyYhpXwt-u9GlFty2AMQ7lxWr1-kSJiPKunD7ldlw9E3KfBfPRIXeg?key=SDlIZXdHeVVxbG9aNHBGay1HeExoTjZsXzZSUUFn

 

Edited June 28, 2019 by agrof

[Mechbuilds]

I don't think i can utilize @Madoca 1977's Fj40's setup on this..  Thanks for the link though. 



Now when i have the wheels attached, i think, should it be one stud longer? 
I might change the wheels due to a little bit of rubbing on the front axle due to the L shaped beam piece when turning. 

[sirslayer]

shorter wheelbase has a better wiggle for your crawler when it gets stuck... :) 

[Mechbuilds]

2 hours ago, sirslayer said:

shorter wheelbase has a better wiggle for your crawler when it gets stuck... :) 

That's true! 


I just can't seem to figure out a way to join these axles together.. It's that middle point with the yellow axle.. 
If i use the same kind of system that @filsawgood's suzuki jimny has, then the axles will start to slide forward and backward when going up and down. 
The pivot point needs to be the same as the U-joint. 
That's where the issues are coming from.. 

I don't want to abandon this project because of this issue with the middle part. 
I'm having problems on where to connect the linkages and how to connect the XL motor because it's one stud too wide so i need to make a 4 stud long gearbox so i can mount the XL engine between the center and the servo so i can have enough room for the battery box. 
If i go with an L motor instead, the crawler will have less torque and more speed which is bad for rock climbing. 


EDIT:

L motor would fit easily.. But it would be fast and not torquey..

Edited June 28, 2019 by Mechbuilds

[sirslayer]

@Mechbuilds this is just a rough draft and I always believe that if you are using 1 Lego PF XL motor then they are always room for 2 !!!!!!   maybe something like this 

 

the red diff represents your transmission 

Edited June 28, 2019 by sirslayer

[Mechbuilds]

39 minutes ago, sirslayer said:

@Mechbuilds this is just a rough draft and I always believe that if you are using 1 Lego PF XL motor then they are always room for 2 !!!!!!   maybe something like this 

 -Snip-

I could fit 2 XL motors. It wouldn't even be hard. There is heaps of space for a second one. 
The issue is the gearbox... By the way. What ever happened to your axle.. Nice.