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Old April 24th, 2016, 06:44 AM
randall555 randall555 is offline
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Default np 203 t case ?

I just picked up a np 203 t case and was going to build a 4-1 doubler with a np 205 but after looking into the cost it easily while be $ 2,000 or more so im not so sure that I will do this . so for my question would the np 203 make a good choice to replace the np 200 thats in our trucks ? what would be the good points and what would be the bad ?
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Old April 24th, 2016, 11:03 AM
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jeeper jeeper is offline

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Is the 203 you got a divorced unit? Rumor has it they exist but I have never seen a divorced NP203.

The 203 is a heavy (as in weighs a lot) chain driven full time 4wd transfer case. They were much more common in married configuration.

One good point is it is relatively strong.

One down side is it is full time 4x4 which means less fuel economy. That also means it would be a poor choice if you wanted to add manual lockers to the axles.
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Old April 25th, 2016, 02:12 PM
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gonz gonz is offline

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The chain is considered the weak link in the 203 as it stretches out, but gets eliminated in the doubling unit with the 205. I've seen a couple of divorced 203s online, but never get to put a bid in on time. Hard to find for sure.
If it is divorced, I would save it and collect change for the doubler. I wouldn't put in the 203 all by itself unless the 200 is toast and you had no other options. Even though it is strong I agree with jeeper about the weaknesses.
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Old April 28th, 2016, 10:59 AM
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Subybaja Subybaja is offline
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FWIW I had 203s in two different 70s Chevys, and liked them. I don't drive a 4x4 for mileage, so the 2-3 mpg doesn't matter, and just like my Grand Cherokee having it there all the time is nice. I do live in snow country, though.

The chain is an easily-replacable wear item, but you do have to do it every 100k or so...

Why so expensive? 205+driveshafts? I thought the 203 planetary was supposed to be the low-buck doubler?
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Old March 10th, 2019, 06:34 PM
roadglide roadglide is offline
Join Date: Jun 2015
Location: Palm Harbor, Florida
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NP203 question? My 715 was converted to Manual locking hubs. Than, I put in a turbo 400 and a NP203. This set up is all time 4x4. This does not have a conversion kit. Does this mean the manual locking hubs should come back off?
Any explanation would be great. Thanks.
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Old March 15th, 2019, 01:03 PM
TXfirefighter TXfirefighter is offline
Join Date: Nov 2012
Location: Tomball, TX.
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Default doubler

I wanted to do the 203/ 205 doubler but I am running a ford front diff (drivers side drop) and finding a divorced Ford 203 is almost like finding hens teeth...
I found chevy and dodge parts but no one builds ford input shafts for the 203.
So, I sat down with my son and added up the cost of the doubler project and came up with a estimated 1400 - 1500 dollars. The Offroad Design magnum box is 1- smaller, 2 - lighter in weight, 3 - provides a lower gearing then the 203/205 and, Best of All, it's only $400 more and arrived with the input and output I needed! It cost me $1900, has a 2.72:1 low range so when combined with the 205 I get a total of 5.33:1 thru the 2 gear boxes. And it took less time than building the 203/205 unit.
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