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| GM NP203 to Bronco Dana 20 build-up, (i might go with a granny 4-speed, SM 420 or SM465 later, but now the project is to use my TH350 with a factory adaptor to the gear reduction section of a NP203 and then build (have made) an adaptor to a Ford Bronco dana 20 why do this? 2.0:1 x 2.46:1 = 4.92:1 TransferCase + 4.56 axles = Ultra Slow 4-Wheeling installation of dual T-cases into 3/4tonYJ on 2nd page |
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| Pictured below is from "Wild Horse's 4x4" site, they call it the "Cold Duck" it's 2 custom Ford Bronco Dana 20's |
| I'm open for other ideas or suggestions, E-Mail me with your thoughts. |
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| This is a bronco dana 20, that i got still hooked up to a broken tranny. |
| below: is the ford factory adaptor, i'll be using the gear and bearing and copying the splined shaft onto the NP203 shaft below |
| Below: the reduction section of the NP203, the long shaft will be re-cut to become the input to the Dana 20 |
| this is the forward end of my NP203, it will adapt to my TH350 tranny with a factory 1" thick adaptor. (there are different inputs, you have to get the one you need) |
| Chris' Jeep Page also an owner of a '89 YJ, with an excellent "Ford 302/NP435/Np203/Dana20" swap (pictured below, without the 20) |
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| Left: Advance Adaptors, has the "Doubler" it also used the gear reduction of Np203 with a Land Cruiser gearbox. |
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| This is Off-Road Design's"Generation 2 Doubler" it mates any version NP203 to any NP205 together their site also has alot of other great stuff |
| below, is a nother version of a Np203 and Np205 this is made by Gordon Pritchard. |
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| Below are Links to other "Dual Transfercase" setups i've found, if you know of others, please send me an E-mail |
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| pictured to the left is the factory Th350 to NP203 adaptor i'll be using, it measures 1" thick. So I started by taking the bronco tranny to Dana20 adaptor (pictured top right) and cut off about 3/4" of the end that mates to the transfercase. then i cut a large section out of the main body of the NP203 also a section about 3/4" thick. (the area that bolts, to the low range box) both were taken to a local machine shop and milled down to about 1/2" thick keeping both surfaces parallel. these 2 pieces and a third section made from 1" alluminum makes up my custom adaptor. ( pictured below disassembled) |
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| Below is the "Marlin Crawler" they use 2 factory Toyota T-cases |
| Below is an adaptor made by "Inchworm" also used to mate 2 toyota T-cases |
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| Pictured Right: Is a NP231 with an additional planetary gear section. there is a very good writeup at Robert Bryce's web page |
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| I just had to get this "Skull shift knob" to use with the NP203 low range box. |
| I used 3/8" treaded rod and nuts to hold everything together with some 1/32" gaskets I made. After taking measurements off the factory ford adaptor that houses the bearing and Dana 20 input gear, I then bolted everything together using the original NP203 low range box output shaft and measured for reference, all measurements and the 2 shafts, bearing and gear were sent to: "Moser Engineering" 102 Performance Dr. Portland, IN. 47371 @ 1-219-726-4159 to get the original NP203 shaft cut and resplined to match the factory Ford input shaft. (new shaft pictured farther down this page) Click logo below to visit Moser's very nice web site: |
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| the picture to the left was taken september 30, 2000. I've decided to put new bearings n' races on the Dana 20 output shaft, thinking it is going to get alot of torque and could use any extra help. (while i have the 20 apart i'm also going to change both output seals and all gaskets) from the picture you can also get an idea of how big the NP203 low range box is comparted to the Bronco Dana 20, it also has got some "Humongous Gears" (add big grin here) below: another picture of the first complete case to case test buildup. |
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| 2 assembled below: left picture has the factory NP203 bearing and centering retainer, this is one of the 2 bearings that will support the shaft re-cut by "Moser". also note the large notch i had to cut in the upper lift corner (Arrow), this is to clear the Dana 20 shift rods. |
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| Gear-Heads |
| This is the first case-to-case trial build-up, i think all will work. |
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| Three shafts below: left: original NP203, middle: cut down NP203, right: factory Dana 20 |
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| this SM420, i'm dreaming of mating to my dual T-case someday? |
| Continue to Page 2, Dual Transfer-Case Installation |
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| this is a Mazda T-case with a "Home made Divorce mounted Dana 18" completed by Alfred. e-mail @ abudschitz@yahoo.com |
| Updated: 27 May 2007, Installed input yoke and converted to "Divorced Mount" Page 3 and installed in 52 Ford "Tator" |