22 to 23 spline crawlbox adapter/coupling for Manual trans to 4.0L Marlin Crawler Tacobox

To be clear, that's exactly what you would have gotten had you ordered from Marlin when they had them...and old inchworm adapter. I do recall hearing about some fitment issues on the spline adapter that caused stripping of the splines, which is why part of why I think Marlin wanted to make their own. That said, there are plenty of folks running the inchworm spline adapters on both Marlin and TG setups without issues.

Do you have a crawlbox already or parts to build one?

 

True, I was aware of that. But I could have made it work or dealt with the consequences.

I have a full top shift gear drive case on the shelf. So I would just need the adaptors.
I had dual cases on my old SAS 94 pickup (3vze, 5mt, 2.7/4.0, 4.88:1, Toyota E-lockers F&R) Current truck wont be quite as crazy, but I miss those dual cases.

I have a welder and access to a tube bender as well, so I can get creative with transfer case mounting.

 

Well I don't have a lot of faith you'll be able to find all the bits and pieces, especially without going to TG for plates, but if you get it all together and need a hand, I'm not far from you and happy to help.

 

I bet marlin can make the plates easy, it's just the gear hobbing for the spline adaptor that's the expensive bit (as you well know)

It's too bad we are such a small group. It would be interesting to get a group buy together or something. Even if it was just getting a shop to sign an NDA and get drawings for the plate and fund the small run ourselves... But thats mostly a pipe dream.

 

It is exactly that. Economies of scale. I couldnt get there for a group buy so I paid through the nose to make it happen. No need for an NDA as I have the design and am perfectly willing to share it free of cost (to anyone EXCEPT Marlin) through my shop and they are happy to provide 1, 5, 10 or 50 of these. I am willing to bet they'd share files to another shop if I asked nicely. I tried, but I couldnt gather 5 people who were willing to commit because (understandably) they could not get their hands on a built unit from Marlin or otherwise.

I am sure there are 5 or 10 people out there who want this mod, but they cant get their hands on a built crawlbox and like me dont have the skills/tools/desire to do it themselves. If you can't produce or get the crawl box you don't make or buy the stupid expensive adapter.

 

back from the dead. dose anyone know where I can get an adapter to put a dana 300 (23 spline female) input
behind my ra60f (22 spline female) output

 

How does a Dana 23 input compare to a toyota 23? If they are the same then my design, or a modified version of it might work. Might need it longer or shorter depending on how things bolt up with an adapter plate. Might need a different extension housing for the seal. Not sure if you've thought about a crawl box, but NWF might be able to help you build an eco crawler with toyota gears in front, adapted to your Dana 300 in the back.

 

yes the nwf eco crawler will work with the dana 300. and thanks for the reply. It's looking like the only other option is to make the dodge d60 into a drivers side with some cutting and welding. I also have a w56 trans with the right side t case behind it bit dont know if that can replace the current trans. I'll see.... thanks

 

NWF is top shelf when it comes customer service and customization depending on customer needs. Eager to finish the eco crawler!

 

Another thing I failed to write down is that I just came across this thread and would like to give mad props to @Littles for the work he put on to make shit happen. Cheers!

 

Appreciate the kind words. It was a fun project and honestly I'm still hurting my arm all these years later patting myself on the back that I nailed it almost perfectly first try, aside from having to grind down that shoulder from square to round on the prototype.

When I got my hands on that marlin box, I hadn't really done all my research on what I needed to mate it up with the manual trans. Timing was bad with inch worm going out of business, parts being in limbo, and marlin being marlin. I knew i needed a different adapter and oil seal housing from the auto, but I had no idea that with inchworm out of business, they pretty much didn't exist and I'd have to make my own. Luckily i had the oil seal housing in hand from a friend. I wasn't going to accept that I couldn't do it because the trans adapter didn't exist. I learned that small batches of customs machined parts are very expensive.

I spent $1000 a piece on two of these silly adapters, on top of $2k for the marlin box and all the other things you need to do to the truck to make it work, like exhaust and drive shafts.

I guess marlin has assembled boxes again and prices have nearly doubled from what I paid. They are $3700 and $3900 for the auto and manual respectively. Would love to see how marlins manual adapter compares to mine, or if he just copied inchworms design.

With those prices in mind, it's hard to argue against that NWF box at $1700 that utilizes a factory toyota input, gears and shift mechanics to adapt to whatever you want behind it, without the need for a sleeve or crazy step down adapter like I made between the tcases for the marlin and trail gear setups.

 

^^ thank you..

 

Facts! MC did not even cross my mind when looking to go doubler. Appreciate their grind and innovation but times changed. NWF paired with 4.56, 35”s and FR locker soothes my needs.

 

If NWF had been an option when this all came up, believe me I'd have dumped that marlin box in a heartbeat to someone with an auto. Not sure if you've seen or followed other threads I've posted in, but as soon as NWF came out with the eco crawler, I was in the first or second batch to get my hands on one. Even after all I went through making that adapter for the MC case, i couldnt wait to rip that shit out and put in a product from a company I believe in. I think that the NWF is far superior in its design, especially in that it uses the factory interface to the tcase/trans over some ghetto ass adapters and aluminum housings and seals, utilizes readily available gears and bearings from toyota, and customer service is hands down better than marlin. The NWF doesn't leak either. The ratio is plenty low for me with 4.56 and 35s like you said. It bolts right up without additional supports and welding a mount off the cross member. Kinda a no brainer for me. I am a big NWF fan boy, big hater on marlin after all this fuckery.

I would really love to see someone do a 4.1 Rubicon case behind an eco crawler. I have thought about it but there's really no compelling reason for me with how happy I am with the current setup.

 

Solid man! Now more itching to get my eco crawler slapped in since as well I’m at 4.56 and 35” chonkers