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General Tech Difference between a TH400 and mopar 400

webyepn

webyepn

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I am trying to educated myself a little more on my Jeep. What is the difference between a TH400 out of a chevy and a 400 out of a Jeep? What exactly is it called out of a Jeep? Is there any advantages over one or the other? Any input would be appreciated.
 
Tacoma

Tacoma

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There is no such thing as a Mopar 400-- Jeep was owned by AMC when they were running TH400's. :D

Jeep TH400's (except some oddball early ones behind the Buick engines Jeep used then) have a round bellhousing, instead of the "home plate" bellhousing used on GM vehicles.
The output shaft will probably be a LONG 10spl (or is it 16? it's been a while) unit for Quadratracs, or the more rare Dana 20 version from the early 70's (used behind Buick 350's in Wagoneers).

This output shaft can be swapped out for a GM unit, and with the proper adapter, you can use whatever GM case you want. Internal parts are interchangeable.
 
Chevycrew

Chevycrew

Well-Known Member
Location
WVC, UT
For example:

My buddy is running an AMC 401, AMC version th400, then via a chevy short output shaft in the th400, a drivers drop 241 case...
 
webyepn

webyepn

gone yeepn
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Tacoma said:
There is no such thing as a Mopar 400-- Jeep was owned by AMC when they were running TH400's. :D

Jeep TH400's (except some oddball early ones behind the Buick engines Jeep used then) have a round bellhousing, instead of the "home plate" bellhousing used on GM vehicles.
The output shaft will probably be a LONG 10spl (or is it 16? it's been a while) unit for Quadratracs, or the more rare Dana 20 version from the early 70's (used behind Buick 350's in Wagoneers).

This output shaft can be swapped out for a GM unit, and with the proper adapter, you can use whatever GM case you want. Internal parts are interchangeable.
Click to expand...

Thank you Tacoma. I will have to crawl under it and see what kind of pan it has.

Is a GM output shaft stronger? I am trying to figure out what case to run. I here that the 400 is a good trany but i really don't care for my D20.
 
webyepn

webyepn

gone yeepn
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orem
So this is the break down on my drive train. Engine 360 Carborated, Trans AMC 400, T-case Dana20. I am thinking of putting together a 205/203 doubler. I need a lower range then what i have. I am running 458 gears. What could I do that wouldn't break the bank?
 
Tacoma

Tacoma

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well.. you'll need a 32spl output shaft... any Doubler will cost you a minimum..$800 for the Doubler and the new output shaft, and the new second crossmember you'll need, plus new driveshafts... and you'll need shifters.... possibly floor mods.

I don't know what the low is on a D20, but the NP241 has 2.72:1, which isn't bad. And they're cheaper than a Doubler. :D
 
Bear T

Bear T

Tacoma free since '93
Location
Boulder, mt
Tacoma said:
well.. you'll need a 32spl output shaft... any Doubler will cost you a minimum..$800 for the Doubler and the new output shaft, and the new second crossmember you'll need, plus new driveshafts... and you'll need shifters.... possibly floor mods.

I don't know what the low is on a D20, but the NP241 has 2.72:1, which isn't bad. And they're cheaper than a Doubler. :D
Click to expand...

x2 Not to mention that on a jeep, you will probably run into driveline angle problems on the rear, the doubler is a long setup and very tricky to make work in short vehicles.:-\

I think you should probably look into swapping out to the chevy NP241 or even an NP208, they both have a 2.72:1. Unless you can find a D300 tcase that might bolt up to the TH400.;)

Just bite the bullet and get a stak mini monster.:D
 
J

jswainthug

Well-Known Member
Location
Murray
I built a double and I am into it $1100+/- and I already had alot of the stuff (the 203 and 205 and shafts). Sure they are bomb proof, but damn its heavy and big. I will never build one again especially if you are tight on space. I would only go atlas or the 4 to 1 kit IMO!
 
Chevycrew

Chevycrew

Well-Known Member
Location
WVC, UT
You can also get a slip yoke elim for the 241 case. You will need the 32 spline output as mentioned, and a th400 to 241/208/205...round adapter.

241 is available in drivers or passenger drop. Depending on what front axle you want to mate it to.
 
webyepn

webyepn

gone yeepn
Location
orem
Tacoma said:
well.. you'll need a 32spl output shaft... any Doubler will cost you a minimum..$800 for the Doubler and the new output shaft, and the new second crossmember you'll need, plus new driveshafts... and you'll need shifters.... possibly floor mods.

I don't know what the low is on a D20, but the NP241 has 2.72:1, which isn't bad. And they're cheaper than a Doubler. :D
Click to expand...

The D20 is only a 2.27:1 Ive been told. And with the 400 not having a very low first gear it doesn't help at all. Th NP241 isn't it Driver drop only. Is it stron enough to hold up to my V8?

Thats what i had in my XJ and I liked it.

CrawlinBear said:
x2 Not to mention that on a jeep, you will probably run into driveline angle problems on the rear, the doubler is a long setup and very tricky to make work in short vehicles.:-\

I thinking I may be ok with my Drivelines were i have a CJ8 but I don't no maybe. Anyone have a mesurment on the lenght of one?

I think you should probably look into swapping out to the chevy NP241 or even an NP208, they both have a 2.72:1. Unless you can find a D300 tcase that might bolt up to the TH400.;)

I was looking at the D300 but they are pretty spendy. And one day I will get a Stak or atlas

Just bite the bullet and get a stak mini monster.:D
Click to expand...

jswainthug said:
I built a double and I am into it $1100+/- and I already had alot of the stuff (the 203 and 205 and shafts). Sure they are bomb proof, but damn its heavy and big. I will never build one again especially if you are tight on space. I would only go atlas or the 4 to 1 kit IMO!
Click to expand...

Can you Mesure it for me?

Chevycrew said:
You can also get a slip yoke elim for the 241 case. You will need the 32 spline output as mentioned, and a th400 to 241/208/205...round adapter.


241 is available in drivers or passenger drop. Depending on what front axle you want to mate it to.
Click to expand...

I have a D44 front end out of a chevy. Its passanger drop. One day i will get a D60:)
So should i Keep the tranny then? Do you have to pull the tranny apart to put in the output shaft?
 
Tacoma

Tacoma

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The 241 is available in passenger drop in 3/4t Suburbans from the later 80's at least. I have one cheap if you want it. :D

You do have to pull the tranny apart, but it needs a rebuild anyway. If not, you can keep it together in subassemblies. Automatics generally assemble from the output shaft towards the front, so you have to disassemble them in the opposite manner to change the shaft out.
 
webyepn

webyepn

gone yeepn
Location
orem
Tacoma said:
The 241 is available in passenger drop in 3/4t Suburbans from the later 80's at least. I have one cheap if you want it. :D

You do have to pull the tranny apart, but it needs a rebuild anyway. If not, you can keep it together in subassemblies. Automatics generally assemble from the output shaft towards the front, so you have to disassemble them in the opposite manner to change the shaft out.
Click to expand...

Ya maybe how much do you want for it?

Ya my tranny needs it anyways. I will miss my twin stick on my D20 though:rofl:
 
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