th400 tailshaft question

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fsjx2
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th400 tailshaft question

Post by fsjx2 » Wed May 12, 2021 7:47 am

Hey guys,

I have a 1974 jeep j10 I'm trying to get going again. A while ago I dropped (took out) the quadratrac to reseal it. One thing led to another and figured I may as well address the tailshaft leaks while I was at it. My problem now is I don't remember exactly what goes in the tailshaft section. I know (and have) the gasket with the six bolts, the ball bearing and large c clip. And I know where they go. But is there anything else that goes in the tailshaft section section before I mount the quadratrac? Like maybe a bushing or seal? I think I remember going in to a Napa parts store and them telling me I had to take the tailshaft section off because I had to measure something because there were 2 sizes of it. But that guy doens't work there anymore. And this was all pre-covid so it's been a while. And I've seen some Very fuzzy diagrams on the web. Some seem to show maybe a bushing of some sort while others don't. And if something else does go in there, where is the best place to get it? And dare I ask, maybe a part number?

I would love to get my j10 on the road again. I miss driving it. It used to put a smile on my face. And even strangers would give me the thumbs up occasionally.

Any help and and/or direction you could provide would be IMMENSELY Appreciated.


Thanks in advance.


ps - it's a th400 is behind an amc360.

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Stuka
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Re: th400 tailshaft question

Post by Stuka » Wed May 12, 2021 7:57 am

You can look at the TSM for '74 here: https://oljeep.com/edge_74_tsm.html

The automatic transmission section has full rebuild steps that should include what you are wanting to know. It also has a section on the transfercase.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Wed May 12, 2021 11:09 am

Thanks for the quick reply Stuka. Ya, that is a great resource. I had already looked at that but thought I would reread it since you sent it. It only has 1 diagram and the verbage says it does have an "output shaft sleeve" and to "remove 2 seals if necessary" . So I'm not sure what that ("if necessary") means? It may or may not have seals?
Screenshot_2021-05-12 7-AutomaticTransmission pdf(1).png
Screenshot_2021-05-12 7-AutomaticTransmission pdf.png
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mjdriver
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Re: th400 tailshaft question

Post by mjdriver » Wed May 12, 2021 12:05 pm

The seals are in the Q track case, the tail shaft just has the bearing and a gasket between it and the transfer case.

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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Wed May 12, 2021 2:59 pm

Thanks Mjdriver. I did get a reseal kit for the Qtrac that has seals. (That was a long story in itself). But there are several sites/places that list an "Extension Housing Bushing" specifically for this application. And they have 3 different sizes (1 5/8", 2", and 1.995" O.D.). So, I imagine it has to be in the tailshaft extension somewhere? And the TSM does state, (remove output shaft sleeve from bearing"). So what is that referencing? I just don't want to put this back together and have a catastrophic failure.

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Re: th400 tailshaft question

Post by fulsizjeep » Fri May 14, 2021 5:05 am

The extension housing is more commonly known as an adapter. The QuadraTrac and Dana 20 used different adapters to mate to the T400. The T400 also used a different tailshaft for QT and D20. ATF in T400 flows all the way to the QT. The 2 seals in the front of the QT are designed to keep ATF in T400 and out of QT and also keep QT fluid from flowing into tranny. This is a common leak area. If one or both seals go bad in front of QT, there is a weep hole between the seals. If you get a leak there, one or both seals are bad. I do not understand the "Extension Housing Bushing" comments and wonder if that is referencing the D20 adapter and not QT. I have torn down many QTs and never seen a bushing for the adapter (extension housing).

I don't get this: "I think I remember going in to a Napa parts store and them telling me I had to take the tailshaft section off because I had to measure something because there were 2 sizes of it." For the QT, there is one size seal and there are two of them and they are installed in the front of the QT.
You can see them in this pic:
Image

The QT section in the Jeep TSM is handy. I have 74 and 77 QT TSM section on my QuadraTrac web page. The 74 is not as extensive as the 77 so I use the 77. There is a link in my signature.
Flint Boardman ~ http://jubileejeeps.org
Embracing the Borg Warner QuadraTrac since 1980 http://jubileejeeps.org/quadratrac
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s, a few Evil Twin mods, http://eviltwinfab.com and a few TT's Fabworks mods, http://www.ttsfabworks.com
76 401 Wag, 77 401 Wag, 77 401 J20
Personally, I like Black Sabbath at 78 speed


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Fri May 14, 2021 6:58 am

thanks fulsizjeep. Yesterday I went out and did some looking and measuring. I came to the conclusion that you and mjdriver are right. There's no way anything else can be in the "adaptor" with the measurements given for those bushings. I also came to the realization that, just like you just stated, " the only thing keeping the ATF from the QT fluid are the seals in the QT".
Now, regarding that weephole. I took my Qtrac to get rebuilt by a Jeep "pro" a while back. And he filled up the weephole with some "gasket maker type product". He said it wasn't necessary and would only cause problems. Any opinions on that?
And, you being a Qtrac pro, do you know how to convert the Qtrac to manual (cable) operation? My engine is not stock (cam, intake, etc) so would feel better with a cable operated Qtrac so I don't have to worry about vacuum pressure.
And, on a final note, thanks to you and Stuka for running, maintaining such a valuable resource (this website) for us old jeep guys! VERY MUCH APPRECIATED!

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fulsizjeep
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Re: th400 tailshaft question

Post by fulsizjeep » Fri May 14, 2021 8:43 am

You are welcome. :-bd

If that weep hole is plugged, you have no way to know if the fluid is being mixed between tranny and QT. To me, that is a problem. My experience is the seals typically get damaged when removing and installing it. People usually don't think much about letting the QT hang on the tranny tail shaft and the seals get whacked. That said, the mechanic should understand this. Plugging that weep hole will prevent him from worrying about screwing the seals up himself.

I run only the factory vacuum shift for Edrive. It is not that hard to maintain. It requires very little vacuum to function properly. It gets source vacuum from the vacuum ball on the firewall. That is shared with the vacuum source to operate the heat and defrost in the cab.
Flint Boardman ~ http://jubileejeeps.org
Embracing the Borg Warner QuadraTrac since 1980 http://jubileejeeps.org/quadratrac
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s, a few Evil Twin mods, http://eviltwinfab.com and a few TT's Fabworks mods, http://www.ttsfabworks.com
76 401 Wag, 77 401 Wag, 77 401 J20
Personally, I like Black Sabbath at 78 speed

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mjdriver
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Re: th400 tailshaft question

Post by mjdriver » Fri May 14, 2021 9:32 am

fsjx2 wrote:thanks fulsizjeep. Yesterday I went out and did some looking and measuring. I came to the conclusion that you and mjdriver are right. There's no way anything else can be in the "adaptor" with the measurements given for those bushings. I also came to the realization that, just like you just stated, " the only thing keeping the ATF from the QT fluid are the seals in the QT".
Now, regarding that weephole. I took my Qtrac to get rebuilt by a Jeep "pro" a while back. And he filled up the weephole with some "gasket maker type product". He said it wasn't necessary and would only cause problems. Any opinions on that?
And, you being a Qtrac pro, do you know how to convert the Qtrac to manual (cable) operation? My engine is not stock (cam, intake, etc) so would feel better with a cable operated Qtrac so I don't have to worry about vacuum pressure.
And, on a final note, thanks to you and Stuka for running, maintaining such a valuable resource (this website) for us old jeep guys! VERY MUCH APPRECIATED!
The only way to convert to a cable or linkage is to fab something yourself. You can do a Google search and you'll see what people have came up with, when I had mine it worked fine and I have a K8600 cam. I don't think it's worth it to convert.

As far as filling the weep hole goes, well I think fullsize jeep answered pretty well.

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Fri May 14, 2021 11:37 pm

The cable conversion project is quite doable requiring some basic fabrication & Welding.
I have not located anyplace that sells New good aftermarket vacuum diaphragms.
An example on YT shows a home made cable setup.
There are some pretty good outlets for nw custom built cables with different various connection end pieces for choices.
I think it’s a better way to go then the OEM setup, faster etc.
Thee also is the 4X2 conversion for TC too, so the cable then would be part of the conversion process.


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Tue May 18, 2021 6:25 am

Thanks 78j10redwhite. I had looked at it a while back and figured I would just get an old fashioned choke cable from the parts store and maybe some angle iron, etc and see what makes the shift happen in the QT where the vacuum diaphram goes in. I'm assuming YT is youtube? I checked out YT but couldn't find the conversion.
On another note, since I have you Qtrac gurus here, the same mechanic who filled the weep hole told me the best way to mount the Qtrac is to split it in half then mount the tailshaft section first, then join the back half of the QT. I pulled it out whole using a transmission jack. Any opinions? Also, I have the rubber gasket that goes between the 2 qtrac halves. should I install this dry or use some type of sealer with it? If so, what type of sealer? I been using permatex aviation sealer for this type of stuff for years but I know there is all kinds of new stuff out there. Plus if you ever have to take it apart, aviation sealer i's pretty messy. I'm all ears.
I should be getting the new poly trans mount and bushings today or tomorrow. The old rubber one just disintegrated when I pulled it off. And getting a new torque bolt thing and qt/adaptor gasket as well. woohoo
BTW fulsizjeep, juileejeeps is the other website I had been racking my brains out trying to remember! And if that's your site, HUGE thanks again for sharing all your knowledge and time! :D You and the people here help us common folk keep these old jeeps running!

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Re: th400 tailshaft question

Post by fulsizjeep » Tue May 18, 2021 7:13 am

You are welcome. The site is old now but still carries the info.

Yes, it is pretty easy to Install front case half, then install chain and sprockets, then the rear half of the case, then the low range (if applicable). I smear a light coat of RTV on the case halves rubber seal. With new seals, you may not need it but I do it for insurance against a leak.

Don't forget there are 2 dowel pins in the case. Don't leave them out.

Image
Flint Boardman ~ http://jubileejeeps.org
Embracing the Borg Warner QuadraTrac since 1980 http://jubileejeeps.org/quadratrac
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s, a few Evil Twin mods, http://eviltwinfab.com and a few TT's Fabworks mods, http://www.ttsfabworks.com
76 401 Wag, 77 401 Wag, 77 401 J20
Personally, I like Black Sabbath at 78 speed

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Tue May 18, 2021 9:55 am

FSJX2,

Here is Youtube vid of an example, it is a fair, not great explanation.
One very important thing I did not see is the proper way to attach cable to this new brace he MFG.
As there is No brace for it unless this example intends to do like the Hi/Low engage side setup use and heavy floor shift mechanism.

https://youtu.be/DfOESXGTe5s
It title is “The original quadratic! why it kinda sucks and its kinda cool"

IMO it leaves some parts out and I would love to see someone redo this video and certain tasks disassemble / reassemble, and show things with perhaps a dimension of the plate & added bracketing that is needed to use a cable.

Though anyone can do the measure and figure out proper pivot measurements and types of connections to make it work.

Yes use oil remove solvent and so the rubber use gasket with "thin coat" of ATV, use both will seal better.
Shouldn’t need to disassemble unit once done now, for at least 150K Miles so don’t concern too much there about messiness.
Check the case mating surfaces for nicks and gouges, smooth out carefully, so no leak spots can develop.

Have a torque chart of all the bolts on hand.
I don’t have a website for repairs or even a YT video for my project, yet is a good idea for others to have so maybe someday will do one.

if I’m going to keep the truck and make it how I want it, the cable setup and 2X4 kit plus front hubs makes it rather more reliable then the OEM diaphragm type.


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Wed May 19, 2021 2:37 pm

Got the transmission mount today. Doing dry fittting and need some direction.
As you can see from the pics, previous owner made swiss cheese out of the crossmember. Anyone have any idea which would be the correct holes in the crossmember? In hindsight, I would have welded up the unnecessary holes Before painting. And taken pics prior to disassembly. But then again, as you can see from the pics, didn't have much to go on. I know I can always install it and hope something lines up but prefer to test fit prior to assembly. I'm assuming the lump/indentation in the crossmember is to clear something else (driveshaft, Qtrac, exhuast) ? Can someone tell me if the lump/indentation faces the front or rear of the truck?
Thanks in adavance.
DSCN5448.JPG
DSCN5449.JPG
DSCN5450.JPG
DSCN5451.JPG
DSCN5455.JPG

1978j10redwhite, thanks for the link. Thats a pretty good setup, I think. Ya, he could have gone in to more detail but doesn't look too hard,imo. Weld some flat stock to vacuum plate and he said he got the connectors from somewhere. And tap the actuator bolt/connector. I don't do snow regularly, but if I did, I would just want to make sure it was all stainlees to avoid rust issues. Or just be vigilant about checking and maintaining. Thanks. I may use that ;)
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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Wed May 19, 2021 3:13 pm

I have 78 J10, TH400,
so have not been under any them to look real close what it looks like.
I’ll PIX the 78 TH400 unit, as it’s OEM and post those so you can see maybe.
Of if you want a spec measurement “point to point” distance I can do this while it's in place too if needed.
As far as the other holes just leave them, shouldn’t affect anything, just cosmetic issue I would presume.

EDITED:

Actually, I have a 79 Wag & 76 J20 which was converted to TH400 from 4sp.
The 78 & 79 TH400 both exactly same and same multi-hole crossmembers and I think are OEM setup, so their mount bolt holes are same location..
The 76 convert 4sp setup is moved over one hole , yet one hole looks like he enlarged it yet is NOT used , perhaps experiment fail on that point?
Likely AMC did as usual, make a Long run of parts like this cross brace, had it designed for many different applications needing this design configuration?
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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Wed May 19, 2021 3:53 pm

thanks 1978j10redwhite. If it's not too much trouble, I think the " spec measurement “point to point” distance" could be VERY useful. But only if it's not too much trouble. THANKS!

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Wed May 19, 2021 4:05 pm

Ok what point to what point would you want ?
My pix show the brace has an angle protrusion, that is a good starting point. I'll get pix and do a measure and try to make it accurate and send it in a few Minutes.

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Wed May 19, 2021 4:46 pm

Measure from frame on passenger - R-side, to 1st bolt “center“ (as in pix next to the angled gusset like area) was 27cm or 10 5/8”. ~ A
Bolt spacing from the #1 & #2 bolt center/center was 4cm or 1 5/8”. ~ B
Bolt spacing from #1 to #3 bolt center/center was 24cm or 9 1/2”. ~ C is not labeled on board.
The row of bolt holes used was towards the Rear of truck.
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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Wed May 19, 2021 7:46 pm

BIIIG THANK YOU 1978j10redwhite! After moving things around and trying different scenarios, I was kinda eyeing those because that's the only way all 3 would line up but there was another set where it was really close. That's hilarious that AMC did that! Now I don't feel so bad about mine. Prior to this, someone had to explain to me why out of all the many cars I've worked on, this is the only one that needs a torque bolt at the transmission mount instead of just being a solid mount. Always good to learn something new I guess. Speaking of, where's your torque bolt? Isn't it supposed to come out the bottom?
Again, HUGE thanks :D for taking the time to do that for me so quickly 1978j10redwhite!!!

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Wed May 19, 2021 9:46 pm

The third bolt AKA torque bolt?
It was there, it was just blocked from lens at my close in position I was at.
My hand drawn pix shows where Mine was located and was 24cm / 9 1/2” from bolt “A”.
Actually new to this term-Bolt yet here I am with three rigs should be aware of it by now!!
Yes, AMC did a few oddball things like the sheet metal screw holding a plate badge on the VC R-side, I thought that was rather unique!
Gotta love our machines.
Glad I was able to help along here on the project, that’s what the forum is about..

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