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Old 10-15-2012, 01:44 PM   #1
|ow|ife
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Automatic to Manual conversion on 4wd

Hey guys,

So my next potential project is a 4wd 75 1/2 ton. The current owner says the stock auto trans (which he's unsure of type, guessing a TH400 though) is slipping between 1st and 2nd.

Motor wise, it's got a 400.

**If I were to get this project I would want to swap in a manual trans just out of personal preference.

>>>My question is this: What (if any) factory 3 or 4 speeds can work with the 4wd transfer case? I'm *guessing* it's a divorced-style tcase given the age, but am not sure. I was told by one person a Muncie 4speed would work but would relish some more discussion and insight on the topic, as well as any builder experience.

Thanks in advance!
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Old 10-15-2012, 05:29 PM   #2
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Re: Automatic to Manual conversion on 4wd

GM used transfer cases that bolted to the back of the transmission. The SM465 4 speed and NP205 transfer case is the correct combination for a manual transmission truck.
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Old 10-16-2012, 07:44 PM   #3
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Re: Automatic to Manual conversion on 4wd

^^^ Agreed^^^
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Old 10-16-2012, 08:38 PM   #4
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Re: Automatic to Manual conversion on 4wd

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Originally Posted by Pyrotechnic View Post
GM used transfer cases that bolted to the back of the transmission. The SM465 4 speed and NP205 transfer case is the correct combination for a manual transmission truck.
I concur. And the SM465/NP205 is a really tough combination.
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Old 10-16-2012, 08:52 PM   #5
x ReAcT x
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Re: Automatic to Manual conversion on 4wd

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Originally Posted by Pyrotechnic View Post
GM used transfer cases that bolted to the back of the transmission. The SM465 4 speed and NP205 transfer case is the correct combination for a manual transmission truck.
x2
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Old 10-18-2012, 01:26 PM   #6
|ow|ife
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Re: Automatic to Manual conversion on 4wd

ooookay then! Commit this knowledge to the mental archives; thanks guys!

The truck I was looking at got sold but there are always squares coming up for sale so when there's one that's just right I still want to do this conversion and in the mean time, I know what to start eyeballing at swap meets or trading friends for.

Thanks!
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Old 10-18-2012, 03:04 PM   #7
Redcap
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Re: Automatic to Manual conversion on 4wd

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Originally Posted by |ow|ife View Post
ooookay then! Commit this knowledge to the mental archives; thanks guys!

The truck I was looking at got sold but there are always squares coming up for sale so when there's one that's just right I still want to do this conversion and in the mean time, I know what to start eyeballing at swap meets or trading friends for.

Thanks!
Look for a hydraulic clutch too. Nice feature to have.
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Old 10-26-2012, 05:24 PM   #8
mickman1977
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Re: Automatic to Manual conversion on 4wd

I swapped a TH350/NP203 for an NV 4500/NP 205 setup. Love the overdrive for the highway and the hydraulic clutch. Got the 4500 out of a 92(?) 1/2 ton (yes, 1/2 ton) and the 205 out of an 86 1 ton. Made a spacer 2.5" thick and bolted them together. Works slick as a whistle. Just be sure to get your yoke angles right after the swap or else you'll be pulling your hair out figuring out vibration issues. (been there, done that)
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