The Mighty Merc – Building the NWF Doubler

After having a D&D Doubler in The Lone Ranger, I knew that I wanted another crawl box in this build. Especially since I intend to run a manual in this rig.

After nearly getting burned on Behemoth Drive Train on another project (thankfully I got my money back out of that deal) I started looking for another supplier. Enter North West Fab (NWF) with their Eco Box:
Sara L.: Driveline &emdash;

This setup uses a donor 231/241 planetary set, ring gear, and shifting mechanism that you dump into their billet housing. In my particular setup, I’m using a 241 planetary set (6 pinion), with a NP271 31 spline input shaft that was turned down (NWF did the machine work) mated to the NP205 that I shaved. Empty case mocked up:
Sara L.: Driveline &emdash;

So this process starts with taking an unsuspecting donor case:
Sara L.: Driveline &emdash;

Remove the planetary gear set, etc, and drop it on the floor:
Sara L.: Driveline &emdash;

Then inflict some violence and hate on the remains until you get the ring gear free:
Sara L.: Driveline &emdash;

There was some water in the case which rusted things up a touch. I soaked the parts in some Evapo-Rust and brought them back to life:
Sara L.: Driveline &emdash;

Sara L.: Driveline &emdash;

I took the ring gear and one of the case halves to work so that I could borrow some press time. It took quite a bit of ‘umph’ to get the thing in there and I don’t think your standard 25 ton home press would be enough to get it done (this was a 50 ton):
Sara L.: Driveline &emdash;

The other half goes together like any other transfer case:
Sara L.: Driveline &emdash;

Sara L.: Driveline &emdash;

Once that was done, I mated the case halves and attached it to the NP205. Note: Pay attention when you put the dang thing together, I had to do this a couple of times to get the clocking right, I blame sleep deprivation due to a new baby:
Sara L.: Driveline &emdash;

I plopped the whole assembly onto the back of the transmission to get a feel for how long the thing will be. It looks like it will be nearly as long as the 4406 that was on it before:
Sara L.: Driveline &emdash;

After playing with the clocking some more, I am going to try to run this orientation (1 notch up from stock) as it should be high enough to keep it above the frame rail, but low enough that I won’t have to hack the floor (I hope):
Sara L.: Driveline &emdash;

For future reference, here are the part numbers for the various seals and bearings in the thing:
– Input Bearing – Timken 110L
– Input Seal – Timken 710928
– Output Bearing – SKF 6307
– Output Seal – SKF 19407
– Shift Rail Seal – ????

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