79 transfer case options.

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toothofwar
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79 transfer case options.

Post by toothofwar »

So my neighbor has an early 80s, late 70s k20 drive line. I have a chance to pick up an np205 for a song. Its matted to a 4 speed right now. So I guess my question is, how much trouble would it be to mat that 205 to my th400. I currently have a quadratrac in it. I don't plan on swapping right away as I'm focusing on body work, but when/if the next q-trac chain stretches I'll be upgrading to something different. I'd like to keep my axles and trans, so would it just be a couple of adapters, or way more work?

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REDONE
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Re: 79 transfer case options.

Post by REDONE »

Way more work. The output shaft of your transmission (TH400) only fits a quadratrac. You have to completely remove all the guts of the trans to change the output shaft. Which output shaft you replace it with would depend on the transfer case you want to go with.
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Re: 79 transfer case options.

Post by toothofwar »

Well darn.... I guess I'll continue the hunt. Do you know of a passenger drop, gear driven case that's even remotely close? I could be swayed on changing the trans if I could get the right adapters. My problem would be $$$. I'm currently selling parts from the 83 to fund the money pit!

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fulsizjeep
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Re: 79 transfer case options.

Post by fulsizjeep »

Probably the easiest gear driven solution would be to find the factory T400/D20 combo in a 71-79 parts donor and swap them out. But do you trust 40 something year old tranny and tcase without going through them? You could just use the D20 output shaft and adapter with your T400. Either way, my preference would be to rebuild them first.
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toothofwar
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Re: 79 transfer case options.

Post by toothofwar »

Oh a rebuild would definitely happen to whichever t case went back in. I'm just looking at the simplest and most cost effective on the install side. I'm wanting the gear driven for dependability. This was my late brother's jeep and I'll be passing it down to my son when the time is right. Also I just rebuilt the q-track about 4 years ago, so it should be good for a bit of I don't draw hide it. Lol

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derf
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Re: 79 transfer case options.

Post by derf »

The only simple swap is another Quadratrac. Everything else is going to require swapping tail shafts in the transmission (i.e. a complete rebuild) and getting the right transmission to transfer case adapter.

Once you settle on changing transfer cases, your cheapest solutions will involve choosing a transfer case that was native behind the TH400, finding a TH400/t-case combo and pulling out the tail shaft and using the adapter in your TH400. The Dana 20, NP205, NP203, and NP208 were all offered behind the TH400 in a passenger drop combo. The three NP cases came behind the TH400 in any number of GM trucks over the years. I know the D20 came in the Jeeps but I don't know for sure if it showed up in GM applications.

Less cost effective but easier to find is buying an adapter kit from Novak or Advance Adapters. You still have to source the case and rebuild the transmission, but it's an easy and straightforward job. And it opens up the options for a great many different cases.
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