th400 tailshaft question

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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Sun May 23, 2021 4:17 pm

I'm baaaack. Got the torque arm bushings yesterday. The raised protruding part is considerably smaller than the hole in the metal bar where it is supposed to sit. Is it supposed to be that much smaller? I thought it was supposed to fit snugly. Also, the vacuum thing that's tapped in to the top of the vacuum plate. Is that just a vent? And do I need to run some tubing so it doesn't sit too low if I go through water? I took some pictures but can't get them to upload to my computer. Thanks


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Tue Jun 22, 2021 12:50 pm

Getting ready to put the Qtrac back on. Just want to make sure the mechanic that did the qtrac put the seals in correctly. (See previous comments) Hoping one of you Qtrac pros could just take a look and make sure he installed them in the correct direction. I ask because they look different than the ones in the pic fulsizejeep posted. And I sure don't want to do this again anytime soon. Thanks guys
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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Tue Jun 22, 2021 1:32 pm

It looks pretty marred up. I would consider slapping in another new seal there.


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Tue Jun 22, 2021 3:47 pm

That is a brand spanking new seal from bj's. So much for my "professional jeep mechanic". I'm really nervous about what he did or didn't do inside my Qtrac now. Thanks 1978j10redwhite.

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Tue Jun 22, 2021 4:07 pm

I Don’t mean to overreact , yet these seals are easy to remove / instal and cost on them is reasonable.
Look it over good as possibly it is only cosmetic mostly and blemishes here, will not Affect seal surfaces.
Have some friend look at it and give 2nd opinion.

Not sure that if you’re concerned about the other aspects of what was done is questionable then do due diligence on questioning things what was done etc, to remove uncertainty.

Don’t let this seal situation be a gauge to the rest of the work done, as it may be just fine actually.
An image can be misleading and seal may be “OK’.
.
Again get a 2nd 'in-person' view and opinion here.

Worst case scenario is, I’ll give you $500.00 for everything if you deliver it to my house.
That might be the best peace of mind and you can enjoy summer more with the extra cash and a new lawn chair and gallon of lemonade in the fridge.!


Topic author
fsjx2
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Joined: Wed May 12, 2021 7:32 am

Quadratrac "Reduction Unit" question

Post by fsjx2 » Mon Jul 26, 2021 12:12 pm

I'm trying to attach the reduction unit to the quadratrac, which is already mounted to the t400. I couldn't get it close enough for the top bolts to grab, so I took the washers off. It was still close, but one stripped the case a little so I took them all off. Is there a secret to getting the reduction unit close enough to the transfer case so it all goes together? Should the reduction lever/shifter be in a certain position, front,middle,back? I read the TSM (both 74 and 77) but couldn't get any more info. I could try tightening the bolts again but I don't want to strip anything more or worse yet, breaking anything. And the sealer is drying as I write this. I really don't want to have to scrape it all off and start all over again so any help is VERY MUCH APPRECIATED. I tried calling local places but no knowledgeable Qtrac guys. HELP!

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Fri Jul 30, 2021 10:43 am

I suggest get some stub bolts and use them to since-pull the piece together then replace with proper bolts once its mated .
Or just use nuts and fasten together, call it good either way. The point is don't use the bolts to TUG it together us stud that already in place so the threads are not stressed too much.
.
It actually should be OK to do this with bolts, so you might have had a bad thread to begin with there.
These pieces sometimes require some jockey around to make parts slide together correctly because the heavy gears internal sag DOWN making things NOT engage correctly.
So you're fighting weighty parts and need to compensate for this downward angle sag possibly.
I perceive you are doing this with it in the truck?


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fsjx2
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Re: th400 tailshaft question

Post by fsjx2 » Sat Jul 31, 2021 1:46 pm

Yep, I'm trying to do it while it's in the truck. The guy that rebuilt it for me said it would be easier to get everything back together if I did it this way (QT first, then install the reduction unit). He also said to give him a call if I had any questions. So I called him, only to find out he passed away about a week before I called him. It's a shame, not only because he was knowledgeable, but was also a down to earth kinda guy. RIP.
I did chase all the threads with thread chasers several times prior to assembly (or trying to assemble) everything. It doesn't use any studs in this location though. Only 6 bolts that bolt directly in to the QT case. And the case being aluminum, I'm afraid to strip it or bust off the tabs/ears. I've spent hours scouring the internet and calling jeep places to no avail.
I've pulled it out countless times and twisted and turned everything I could think of. And even read somewhere online that if you removed the pto cover, that it would slide in. Well, not this one. And I know you're right about gravity. (And my arms, chest and shoulders can all confirm it, lol).
After days of coffee and pondering this, I'm thinking I only have 2 possible solutions. 1) just get a cover for the QT and leave the reduction unit off. I would keep the reduction unit in case I ever sold the truck and the new owner wanted it. OR, 2) take it all (transfer case, cross brace, mufflers, etc etc) off again, scrape off all the sealant I just put on it (big UGH) get new seals/gaskets, and hope and pray I can assemble it all on a bench, and put it all in as one unit.
As always, Big Thanks 1978j10redwhite. If I can ever help you with anything, just let me know my friend.

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mjdriver
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Re: th400 tailshaft question

Post by mjdriver » Sat Jul 31, 2021 2:10 pm

When I did mine I had the same problem, I used a block of wood and a hammer and tapped it on untill the gap closed. Now NO you are not supposed to do that, so try it at your own risk. My transmission output shaft splines and sun gear splines would not agree with each other, as mine didn't come with a reduction unit from the factory. The splines were worn differently cousing them not to slide together. Everything worked fine on mine, but I'm not saying it can't damage things.

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Topic author
fsjx2
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Joined: Wed May 12, 2021 7:32 am

Re: th400 tailshaft question

Post by fsjx2 » Sat Jul 31, 2021 2:23 pm

Hi mjdriver,
when you did that, did you tap on the rear of the reduction unit with the wood/hammer? And did you support it from underneath (jack or blocks or something) while doing that. I'm willing to try just about anything new/different at this point before having to pull it all out and redo it.
Hmm, I wonder if he replaced my sun gear.....
LOL, don't worry. I try this (and everything else) at mine own risk.
Thanks!

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mjdriver
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Re: th400 tailshaft question

Post by mjdriver » Sat Jul 31, 2021 2:40 pm

fsjx2 wrote:Hi mjdriver,
when you did that, did you tap on the rear of the reduction unit with the wood/hammer? And did you support it from underneath (jack or blocks or something) while doing that. I'm willing to try just about anything new/different at this point before having to pull it all out and redo it.
Hmm, I wonder if he replaced my sun gear.....
LOL, don't worry. I try this (and everything else) at mine own risk.
Thanks!
If I remember correctly I had that little cover off the back of the reduction box, and I put the wood on the machined flats under the cover. I tried my best to support it with one hand.

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1978J10REDWHITE
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Re: th400 tailshaft question

Post by 1978J10REDWHITE » Sat Jul 31, 2021 5:36 pm

Not sure how heavy the TC is, maybe 100 pounds, Perhaps consider remove it IF possible , then install your hi/lo hub then reinstall the entire TC .?
At this point this might be the better thing to do.
Seems like redoing it two or three times is a hassle yet this seems like the only real resolve and get it done right..

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