Nissan Pathmaker OneTon SAS Build – Part 5

The Nissan Pathmaker OneTon SAS Build – Part 5 – Case’s N Such

I tackled the easy stuff and avoided doing a bunch of the difficult things. Now I had a bunch of head scratcher things at the same time. First on the list was figuring out the NWF TX-10 to Dana 300 adapter. For those of you new to the world of extreme offroading that is is a unit that I can attach to my stock Nissan transfer case and allow me to bolt a second t-case to it. The reason for this is it DOUBLES your low range. Now I can go in “Low/High” or “Low/Low” (low gear in both transfercases). Why you want that is to get a better crawl ratio. When you have a heavy rig without a ton of horsepower then you can use the torque from the dual cases to help crawl up things and spin your tires faster! Its been a long time mod in Toyota’s but there is still not much aftermarket for the Nissan side of things. Which brings me to my good friends over at North West Fab.

This being literally one of the first units he built he didn’t have any instructions made up yet. Once I pulled the TX-10 apart and cleaned everything up it all became a bit more clear. 

The shaft that connects the TX-10 Crawlbox to the doubler is a piece of art. (It has held up to all sorts of abuse over the next 8 years and is still holding up great!) After a bunch of head scratching I got doubler figured out and mated together. Sorry I don’t have better instructions. They are now included in the doubler from NWF so hit them up if you need a step by step! As part of the doubler is included a clocking rig, which allows you to decide which angle to run your d3000. In this case I planned to go full flat belly so thankfully I left my 1.5″ body lift in.


Oh Dana300, how I love and hate you both at the same time. While I love my D300, which I run flipped upsidedown so I get a drivers side drop output, it does have a few drawbacks. I learned the hard way that this particular unit was the unicorn!


Years later on a wheeling trip I blew up the rear output and I ordered a brand new 32 spline JB Conversions. I tried to bolt it to this unit to find out that this was what they call “The Texas Bolt Pattern” D-300. Of all the years they produced the d300 for one year they had one of the bolts on the rear output in a different location due to a speedo change. Meaning long down the road I had to buy a whole new d300 for $300 just because of that one damn bolt! 

D300s are fantastic tcases and are actually what the Atlas cases are modeled after. They are designed to run passenger drop, so with the Ford axle in the front I run the t-case upsidedown. It still works fine I just had to relocate the breather. Add a sight-tube and replace the shift rail seals so they stopped weeping. I also learned that I had to JB weld the shift rail caps in because when you run your case upsidedown it compresses the fluid behind the rail and can push the caps off very easily.

Slipped the d300 on the trans to see how it would all fit. Happy with it and because of the clocking ring I can clock it for a full flat belly. Also modified the stock Nissan lever guide so I could use the crawl box for just Hi and Low Range.


Tucked it all up inside to see how it’d fit. I took the 3″ body lift and turned it into a 1.5″ body lift. Just to give a bit more room for everything to tuck up, but not end up too tall. You can also see the sweet sight tube that comes on the NWF doubler. Great to keep an eye on the fluid level and I installed one on my d300 too.

Next up it was time to “twin-stick” the d300, which would essentially allow me to go into front wheel drive only and disconnect the rear. Sometimes in really right spots its nice to be able to do a front “dig.” All it required was some time on and a bit of grinding on the shift rail so the “pills” will line up properly. Allowing you front wheel only, but also stopping you from going in High and Low at the same time.

Once I got it all bolted back together it was time to start the fabrication of the 3/16″ belly pan and cross member to hold it all up and protect it.

7 years later

Heres the benefit of me writing this 7 years later. Since the time I’ve thrown this case in I’ve learned a few things. 42″ tires, 4.10 diff gears and a heavy right foot are not going to help the longevity of your D-300 internals. On my second trip out I blew up the rear output. Sheared the shaft right off, leaving me stuck in only frontwheel drive for the wheel back to the trailer. When replacing the rear output to the 32 spline JB Conversions output I learned about the Texas Bolt Pattern I mentioned above. A few trips later I grenaded the front output and most of the internal gears, lucky for you guys I got that one on camera:


I wanted to pick up some new internal gears for my d300. Finding out they were months behind on production I opted instead to change the 4.10 diff gears into 5.38’s and it has made a huge difference in my rig. The torque feels like it did when it had 35″ tires and the 4.37s so its much snappier for the full throttle launches. The steeper diff gears take a ton of strain off your t-case so now after another 15 runs with this set up I’ve had zero problems!

Now onto the next post where we get into building the flat belly and welding up the axles………can you say, proper redneckery?!

Check out Part 6 in the next blog post here: Pathmaker Build Part 6 – Flatbelly and the BBQ

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