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Old 10-03-2012, 04:52 PM   #1
76k10
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Discussion - NP203 Transfer Case Failures

If anyone has broken a NP203 transfer case internally, please tell us how.

I feel like the 203 has a bad reputation, but (like a 12 bolt) I never hear about them actually breaking.
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Old 10-03-2012, 05:10 PM   #2
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Re: Discussion - NP203 Transfer Case Failures

I have only had one that broke. When you spun the tires locked in 4 wheel drive it would make a ferocious clunking sound. I didn't take it apart to see what actually was going on but I figured it was probably the chain jumping around but not sure. The problem with the one I have now is that there is some slack in the chain and clunks when going into reverse. This case has been in full time four wheel drive configuration since 1979.
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Old 10-03-2012, 05:16 PM   #3
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Re: Discussion - NP203 Transfer Case Failures

I have owned a few vehicles with NP203s over the years. Chain failures, drive sprocket failures and windowing the passenger side of the low case section are all pretty common. They also burn up fairly easily, even with a lightweight oil.

They are one of the first things I swap out.
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Old 10-03-2012, 05:21 PM   #4
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Re: Discussion - NP203 Transfer Case Failures

Best thing to do is stay away from them. The two i had the chain and sprockets went. The last one i had i put a part time conversion in it and it did last longer but not by much..
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Old 10-03-2012, 07:33 PM   #5
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Re: Discussion - NP203 Transfer Case Failures

The high/low box is run with NP205 all the time to make a doubler setup, and in that format they are tough. So it looks like the chain and sprockets is the weak point, but obviously, the chain is the weak link in most of the chain drive cases. If it's in good shape, just run it.
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Old 10-03-2012, 07:36 PM   #6
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Re: Discussion - NP203 Transfer Case Failures

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The high/low box is run with NP205 all the time to make a doubler setup, and in that format they are tough. So it looks like the chain and sprockets is the weak point, but obviously, the chain is the weak link in most of the chain drive cases. If it's in good shape, just run it.
Mine is in good shape, I just like reading about this stuff.
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Old 10-03-2012, 07:46 PM   #7
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Re: Discussion - NP203 Transfer Case Failures

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Originally Posted by 76k10 View Post
Mine is in good shape, I just like reading about this stuff.
Go with what Redcap says. He gets everything for cheap and nothing ever fails.
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Old 10-03-2012, 07:50 PM   #8
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Re: Discussion - NP203 Transfer Case Failures

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Go with what Redcap says. He gets everything for cheap and nothing ever fails.
In a perfect world, I would. I am not in a situation where I can spend any money on fun stuff, so I am having to make the best of what I have.
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Old 10-04-2012, 05:25 PM   #9
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Re: Discussion - NP203 Transfer Case Failures

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Go with what Redcap says. He gets everything for cheap and nothing ever fails.
Ha! I only know what works and holds up due to things failing. As for cheap...well, that is true. There are a ton of these trucks laying around in these parts and, most of the time, people are real willing to deal considering the economy.
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Old 10-04-2012, 10:26 PM   #10
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Re: Discussion - NP203 Transfer Case Failures

I had the 203 rebuilt in 1985 when I put it my 59. The mechanic (good friend now deceased RIP) upgraded the chain and put in a Doug Nash part time kit. It was my daily driver until 2000, about 7K miles a year including camping and hunting in some pretty rough stuff, When I had it out I checked it and the chain is a little loose but not enough to warrant tearing it apart. The full time shaft conversion keep the load off when in 2wd. When they stretch under load the chain will jump the gear (that is the bang) and, I assume eventually break or hand grenade the case. I have also read that the cheaper part time conversions that use the wafer bearing fail over time because the bearing breaks down allowing the internal part to move and lock up causing havoc. IF I had it to do over I would go with a 205 set up but I am not that ambitious and have a good spare ready to go that will probably last the rest of my life, the next owner can do what he wants. The biggest pain is the shifter, it is a rube goldberg affair with sliding cams that get loose and crudded up. Then you get to spend a lot of time getting underneath with a big screwdriver to pry the levers back into place. I converted mine to a twin stick so there are no cams, just two mechanical levers that pivot.
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Old 10-04-2012, 10:33 PM   #11
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Re: Discussion - NP203 Transfer Case Failures

I have found a good spray of WD40 down the shifter boot will free the stock shifter up. Mud is an enemy of those shifters.
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Old 10-16-2012, 12:29 AM   #12
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Re: Discussion - NP203 Transfer Case Failures

i have destoryed 3 203's before i swapped it out for a 205. the chains would always slip and on two of them i broke the front output shafts. but i ABUSE mine it is strickly a mud truck so it always under alot of load at the time i was running 35x15.5 thornbirds i also had alot of problems keeping my 203's in low range too
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