Peterbilt 6x6 Medium Hauler

[Tommy R]

Originally Posted by huber1918

Awesome Build! Cannot wait to see the progress! Gives me some ideas for my Globe Liner.

Thanks!

Originally Posted by TRUCKMAKER

Check out posts 42-44 in the link below to see what I did, if you look close you'll see that I took the lower rear case screw off the transmission. You will have clearance issues if you don't lift the trans mission which will be the case with any t-case you use. I'm not a fan of the Tamiya 3 spd due to its space sucking size, so this one is going away soon. You might also notice the spring pack on my steer axle . The extra height was in my favor but not so much in yours.

http://www.rctruckandconstruction.co...?t=9138&page=3

I see what you mean about raising the tranny. Looks like clearance for the driveshaft would still be tight at full bump, but I won't be jumping this thing so maybe that's not a big deal. Ha! Do you have any more pics of how you put together your front suspension? Is that a TLT in there?

Originally Posted by scottyk

That ride height addition is what turned me off from doing the 6x6 on my Mack build

Yours is looking very good! Nice work man

Thanks! I'm trying to keep the ride height within reason, but fully expect it to be noticeably taller than a stocker. I'm thinking maybe 3/4" or so, but the Lesu tires may be taller which may raise it more. Not really sure how their diameters compare to the stock Tamiya tires.

[Tommy R]

Didn't have much time to mess with the truck until this evening and when I did I decided to focus on my gear reduction and transfer case solution. First things first I looked into how the tranny is going to interfere with a front driveshaft. Obviously, that's definitely got to be addressed!


I think I've narrowed down my drivetrain choices to these:
1. Use an Axial 2.6:1 trans as a transfer case and possibly a 2:1 planetary gear reduction in front of the Tamiya transmission.
2. Use a planetary gear reduction (probably 2:1) and add a t-case like the 2.18:1 RC4WD Disruptor or the 2:1 t-case from wtbcar.com:


In either of these solutions, the stock Tamiya tranny needs to be raised up fairly substantially....for two reasons. As mentioned, the tranny will prevent a driveshaft from reaching the front axle, but the 2:1 planetary will hit the steering/shifting servos because it'll push the motor forward. My best guess shows a height of 15-20mm is needed. Here's a rough approximation of the height required:


The floor will need to be trimmed, but I'm okay with that. I can always just build a simple cover for it so the trans is hidden from sight. My first estimation of where it'll need to be cut (everything within the white markings).


So before I order some standoffs I made some temporary 15mm spacers to see how that would work.


Driveshaft clearance should be okay with the trans raised 15mm, especially since the trans output will be fairly low.


Front view showing the height of the motor compared to the servo. It'll be reeeeally tight, but I can easily add a few more millimeters of spacers if need be.


Thinking this is what I'll need to cut away to accommodate the new trans height.


So now I need to decide what to do about the transfer case. I have an Axial trans so that's the cheapest solution. I'll just have to fab up a bracket for it. And it'll definitely get the outputs low enough to clear the stock trans. The wtbcar.com t-case looks like it would bolt in after drilling a couple holes so that'd be super easy, but it would cost me ~$50 and time to wait for shipping from (presumably) China. Not sure I'm patient enough to do that. Ha!