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I have a few questions on the TH400

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Old Mar 17, 2008 | 08:54 PM
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Default I have a few questions on the TH400

I am working on purchasing a TH400 but I am unsure which one I need. I assumed they were all the same as long as it was a 2wd set-up. However I am seeing some crossmembers that say "short tail shaft" only. How do I know if it is a short shaft tail or long? And why does this matter if the transmission mount is before the tail shaft? Well I found the link below and it says a "C Shaft", "D Shaft" and a "13in Shaft" It looks like the distance to the transmission mount is different.

https://ls1tech.com/forums/showthrea...ighlight=th400

How do I know what to look for when looking for a transmission? If I buy a BMR cross member for a TH400 which TH400 will it fit?

Thanks
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Old Mar 17, 2008 | 10:23 PM
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4" = short

Then there is a think a 6" and 9" tailshaft The tailshaft is the rear most housing (and output shaft) that bolts on to the tranny case with bolts. The only difference is you would need shorter driveshafts for the longer tailshafts and yes the tranny mount is located on the tailshaft housing...
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Old Mar 17, 2008 | 10:29 PM
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Thanks

Yes I know what a tail shaft is. However the Th400'd I have been looking at have the tranny mount on the housing and not the tail shaft. This is why I am wondering why the tail shaft length matters. What am I missing?

I will see if I can find some pictures
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Old Mar 17, 2008 | 10:59 PM
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The piece with the tranny mount and the tailshaft seal is the tailshaft housing. That will vary in length with the actual output shaft
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Old Mar 18, 2008 | 11:10 AM
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did you read my faq?
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Old Mar 18, 2008 | 01:23 PM
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Originally Posted by 2w0s060
Thanks

Yes I know what a tail shaft is. However the Th400'd I have been looking at have the tranny mount on the housing and not the tail shaft.

I will see if I can find some pictures
Find some pics because no TH400 ever came with the trans mount on the case. From 1964 and newer, none.
They also don't come with 6" tail housings. Either 4, 9, 12.
Sounds like you're looking at th350 cases.
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Old Mar 18, 2008 | 04:26 PM
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Originally Posted by dlove
did you read my faq?
He has put together one hell of a FAQ on this subject...complete with pics, diagrams, blueprints, specs ....anything you could want on this subject.
J
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Old Mar 18, 2008 | 06:57 PM
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Originally Posted by dlove
did you read my faq?
I looked at a few of them but didn't find the info I needed. Can you please post a link to yours, I appreciate it.
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Old Mar 18, 2008 | 06:58 PM
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Originally Posted by 9000th01ss
Find some pics because no TH400 ever came with the trans mount on the case. From 1964 and newer, none.
They also don't come with 6" tail housings. Either 4, 9, 12.
Sounds like you're looking at th350 cases.
I will get a pic, I have a a TH400 here that is empty and a TH350.. the 400 is 7-8" longer.. I was told it was a 400 at least. I will post some pictures shortly.

So TH400 have the transmission mount on the tail shaft?

Thank you,
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Old Mar 18, 2008 | 07:18 PM
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Yes the th400 mount is not on the case. They also have a four bolt governor cover on the passenger side, an aluminum tag on the pass side (if it hasn't been removed), the vacuum modulator is on the pass side almost opposite the shift linkage. It has a six bolt tail housing.
A th350 has the mount, has the vac mod on the pass side toward the rear, also on the pass side it has a round accumulator. It has a 4 bolt tail housing.
I'm sure you could find a pic on google pics to save time of making your own.

TH400 pics http://images.google.com/images?q=th...-8&sa=N&tab=wi

TH350 http://images.google.com/images?um=1...=Search+Images
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Old Mar 18, 2008 | 07:22 PM
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Originally Posted by 2w0s060
I looked at a few of them but didn't find the info I needed. Can you please post a link to yours, I appreciate it.

https://ls1tech.com/forums/automatic-transmission/815618-th350-th400-frequently-asked-questions.html

if it's not in there, let me know what you find and i will add it
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Old Mar 18, 2008 | 07:43 PM
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Originally Posted by dlove
https://ls1tech.com/forums/showthread.php?t=815618

if it's not in there, let me know what you find and i will add it
There is no reference to a non chassis mounted torque arm.
It's mentioned and I know there are kits to mount it to a th400 tail but nothing is said.
(I'd personally use a chassis mounted but to those who might not the info isn't there).
There is also reference to not wanting the thread to turn into 10 pages of questions and comments but then there are links that take you to threads that ARE full of questions and comments, like the speedo.

And thats another thing, there is one part number listed for the reluctor wheel, I'd assume it's the 27 spline since it's the same as the original 4L60E, but there is a different reluctor wheel for guys running the 4" 32 spline tail. It could save someone some trouble down the road to note the two and find the p/n for the other wheel.

Some builders do recommend using a vac mod with manual valve bodies only to regulate line pressure at low load. May cause confusion if someone bought a mvb trans and it had a modulator.

Somewhere in the links to links to links I seen a question about needing a different pilot bearing for a th400

This link leads to the best write up so far.

Last edited by 9000th01ss; Mar 18, 2008 at 07:49 PM.
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