• Welcome to RCCrawler Forums.

    It looks like you're enjoying RCCrawler's Forums but haven't created an account yet. Why not take a minute to register for your own free account now? As a member you get free access to all of our forums and posts plus the ability to post your own messages, communicate directly with other members, and much more. Register now!

    Already a member? Login at the top of this page to stop seeing this message.

Small compact 2wd/4wd Neutral/Drive "dig" unit?

TITANIUM94010

Quarry Creeper
Joined
Dec 28, 2019
Messages
375
Location
California
Sorry for the bad wording, but does anybody know of a small "transfer case" that lets you toggle between connected and neutral?

Something that goes between a transmission, driveshaft and a diff,

So in the "locked"setting, the transmission sends power to the driveshaft, to the "unit", to the other driveshaft and to the axle.

And in the "neutral" setting, the "unit" stops power from going to the axle and leaves the front axle freewheeling


Power transmission In "locked" position
Transmission---->Unit---->Axle




Power transmission in "neutral" position
Transmission>Unit-----X-----Axle


I'm using it for a custom 2wd/4wd setup. The transmission is a RC4WD AX2. unfortunately, something like the SSD locking hubs wont work, as I'm using a custom mounted Slash 4x4 front IFS, and not a normal crawler axle.

Thanks!`






Edit: If it makes things more clear, I'm trying to find something that will let me toggle between having power being sent to the front axle.
 
Last edited:
The Phoenix transmission is the only one I know of that actually accomplishes all that aside from the compact part of it.

Aside from a transfer case I assume you'll run something like a TGH forward motor mount? Whats the plan there?

You may be able to pair down the Phoenix transmission into just a transfer case if you are into experimenting. That actually sounds like a fun project.

EDIT: oops I see you dont need dig in addition to selectable 4WD, ben h has the right idea.
 
Last edited:
Small compact 2wd/4wd Neutral/Drive "dig" unit?

Thank you for the replies,

I probably should have included a photo, but I already have a main transmission.

I need something very small to fit between the transmission and the front diff where the current driveshaft is. The original idea for a selectable 2wd/4wd was to have a needle roller bearing that would move the little piece of driveshaft that shifts from front to back, but I learned the hard way that roller bearings are not made to take ANY horizontal stresses.

f4a625a4bedd6bd4480e82fdb4211e29.jpg



The closest thing I've found is the boom racing transfer case, but it's meant to be an actual transfer case that's meant to have the power be fed from the motor input shaft.


https://www.boomracingrc.com/swd-transfer-case-kit-192012
There is a chance that it might work with the input going in to one of the output shafts, but I'm not sure.


If I have to go with shifting it manually, well there's no way to get around that, but hopefully I can figure out a way to make it servo powered.
 
Last edited:
Maybe not the way the OP wants to go, but a simple 3-gear dig gearbox (namely the Que-T from Amazon) flipped round forward, with the "dig" locking dog left out. So in "normal," the driveshaft would be fully engaged and you'd have 4WD, but in "dig," the front driveshaft would be disengaged and just free-spinning. I realize this does nothing to address the 2-speed. I know Cross makes a transfer case with dig in it, but Cross parts support is non-existent domestically, and I don't actually know if they even sell it separately.

Hot Racing makes a 3-position dig unit for the Wraith gearbox, and that trans looks really similar to the AX2, but I don't know enough about 'em to say if they're the same. Worth a look, I think.
 
Maybe not the way the OP wants to go, but a simple 3-gear dig gearbox (namely the Que-T from Amazon) flipped round forward, with the "dig" locking dog left out. So in "normal," the driveshaft would be fully engaged and you'd have 4WD, but in "dig," the front driveshaft would be disengaged and just free-spinning. I realize this does nothing to address the 2-speed. I know Cross makes a transfer case with dig in it, but Cross parts support is non-existent domestically, and I don't actually know if they even sell it separately.

Hot Racing makes a 3-position dig unit for the Wraith gearbox, and that trans looks really similar to the AX2, but I don't know enough about 'em to say if they're the same. Worth a look, I think.

Thanks for the reply,

I checked out the gearbox on amazon, and I think it would work, only its much too big to fit in a space that small.

I think the boom racing transfer case may work when powered from one output, but the two outputs are offset.

I may just end up doing a manual toggle, but if anybody has an idea that would remotely work, please post it!
 
I've seen VFD twin transmissions for as low as $120 on Facebook. Removing the top shaft and replacing it with Axial part #AXI31410 will turn it into a transfer case.

I have 2 of those transmissions so far, because of the 2wd option. I'll be getting a third to use as a transfer case with a forward motor mount in a wraith/bomber based truck. Just waiting for the phoenix trucks to finally come back in stock.
 
Losi comp crawler transmission can be molded to 4wd, fwd, rwd.
 
Hey TITANIUM94010 I would suggest you consider starting with the Transfer case/transmission that meets your requirements then figure out what transmission would work for it (if needed). You're shooting down just about every option you have because of your transmission. I just dont see anything fitting in the space you want it to (if you keep the AX2).
 
Back
Top