700r4 or TH400? (1 Viewer)

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So I am getting ready to pick out my transmission for my 73 FJ40 build and have seen allot of people recommending the 700r4. However, I have access to a TH400 and the TH400 seems like its a better pick since it seems more stout, parts are cheaper and it was put into 3/4 ton trucks. The 700r4 was put into 1/2 ton and is more expensive. However, the 700r4 has an over drive and a lower first gear. I really don't see the need for the over drive on a rig that will be driven mostly off road but I do see the benefits of the lower 1st gear.

What are your thoughts?
 
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I should also add this is going to be mounted to a built 350 chev and I am going to be getting a tyota split case.
 

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700R was in 3/4 ton and one-ton as well...






If you run a 700R/4L60 you will need to move the rear axle back to make room for a drive shaft.




:meh:
 
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700R was in 3/4 ton and one-ton as well...






If you run a 700R/4L60 you will need to move the rear axle back to make room for a drive shaft.




:meh:
Does the same go for the TH-400? Does it come to close to simply shorten the driveline?

Thanks for the help.
 
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700R was in 3/4 ton and one-ton as well...






If you run a 700R/4L60 you will need to move the rear axle back to make room for a drive shaft.




:meh:
Also, I heard you where the guy to talk to about getting a good split case for my build.
 
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I'm running a 4l60 with a Marks adapter & 60 series transfer case.
Here is a pic of the rear shaft in my shorty with the rear axle still in the stock position while it was on the hoist a little while ago.
Photo0099.jpg
 
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I'm running a 4l60 with a Marks adapter & 60 series transfer case.
Here is a pic of the rear shaft in my shorty with the rear axle still in the stock position while it was on the hoist a little while ago.
Holly molly, lol. It is a short drive line!!! any issues with it being at that sharp of an angle? Also, looks like you lost a fair amount of ground clearance.
 
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I'm running a 4l60 with a Marks adapter & 60 series transfer case.
Here is a pic of the rear shaft in my shorty with the rear axle still in the stock position while it was on the hoist a little while ago.
It almost looks like your axel is resting on the drive line. Is this true?
 
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Holly molly, lol. It is a short drive line!!! any issues with it being at that sharp of an angle? Also, looks like you lost a fair amount of ground clearance.
I did lose a bit of clearance but for the wheeling I do it has never caught me up on anything. If anything under my car gets caught on stuff it's the diffs. The tail shaft has never bound up on itself or dropped out & the angle in the pic is because it's on a hoist & there is no weight on the suspension. I would've like to get the engine & transmission up higher but it all came down to the angle & length of the rear drive shaft. I might have a look at moving the rear axle back maybe but for now it works the way it is.
 
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I did lose a bit of clearance but for the wheeling I do it has never caught me up on anything. If anything under my car gets caught on stuff it's the diffs. The tail shaft has never bound up on itself or dropped out & the angle in the pic is because it's on a hoist & there is no weight on the suspension. I would've like to get the engine & transmission up higher but it all came down to the angle & length of the rear drive shaft. I might have a look at moving the rear axle back maybe but for now it works the way it is.
Do you get any vibration? will it still alow your suspention to flex all the way? What if you did a SOA, would the angles of the driveline still be ok?
 
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I did lose a bit of clearance but for the wheeling I do it has never caught me up on anything. If anything under my car gets caught on stuff it's the diffs. The tail shaft has never bound up on itself or dropped out & the angle in the pic is because it's on a hoist & there is no weight on the suspension. I would've like to get the engine & transmission up higher but it all came down to the angle & length of the rear drive shaft. I might have a look at moving the rear axle back maybe but for now it works the way it is.
One more question, sorry, lol. If you had to do it again would you still go with the same setup?
 
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What if you did a SOA, would the angles of the driveline still be ok?

ouch,............................ anything could be done

as previously stated, some lengthening would be in order. just to fit the DC's that is. better off with the thinner adapter if applicable.
 
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ouch,............................ anything could be done

as previously stated, some lengthening would be in order. just to fit the DC's that is. better off with the thinner adapter if applicable.
I guess moving the axel back would prob be the best idea then if there is a SOA.

I do plan on doing an SOA on my rig so I guess I better start doing some research on pushing the axels back.
 
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arg, what a pain it is to find info on this convertion.

Well I am serriously thinking bout sticking with the stock 3 speed and upgrading the trasnfer case only.

What do you guys think?

Is there a way to beef up the stock 3 speed?
 
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I set mine up with an angle finder, however I did get a small vibration after fitting my extended shackles ( I get more vibration out of my tyres then anything ). I did think about SOA when I was originally building the shorty but wanted to keep my COG as low as possible, plus the rear axle would've had to go back a fair way.
Because the drive shaft is so short I used a later model 45 rear diff housing & axles because the housing has 4 bolts that hold the rear brake backing plates on & then I fitted 60 series rear brakes & I have my hand brake on the rear axle.
As for doing it again I would probably still use a 4l60. I have a mate with a 45 series with a t400 in it & his has a different adapter for the transfer case, it is a shorter adapter then mine but the overall length of the transmission & transfer case is only 4"shorter then mine.
Mine still flexes pretty good, the rear doesn't quite flex as good as the front but like I said I haven't had a problem yet.
As for finding info of the conversion, I originally did mine about 12 years ago & there was next to nothing back then. Hell I didn't even have a computer to look up info on so my research was all done buy telephone & trial & error.
 
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any reason for the automatic??? I did the SM465 with the Marlin Crawl-Box, the sotck 4 speed transfer case with he case saver, due to my V-8 and my right foot. I did do a SOA with Alcan springs amd moved the centering pin rearward 2 inches. when you mock up the rear diff remember that you need equal and opposing angles of the ujoint flanges to remove the vibration then weld in the spring purches. Youll be happy after your done when it drives smooth.
 

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