post #1 of Old 06-14-2013, 07:46 PM Thread Starter
paulbone
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1977 FSJ Cherokee 
 
Join Date: Mar 2012
Location: las vegas
Posts: 22
Quadra Track vacuum shifter

Do we have any QT experts in the room?

I just rebuild me engine, put it back in and got it running, but now the Jeep won't drive.

I can hear the big 'clonk' as she goes into R or Low 1. I checked the vacuum lines and found the rubber had split and snapped off by the control mechanism on the transfer case.
I put new hoses on and can feel vacuum, but she won't lock and drive. Two weeks ago when I was driving her, I had no problems.

Could the diaphram have gone all of a sudden?

I have a 76 Chief as a spares car which also has a QT, however I notice that there are only two vacuum lines at the transfer case end, where my 78 has three. The third runs to another vacuum source on the manifold, in addition to the glove box switch vacuum source.

Is this normal does anyone know?

Also has anyone tried and tested a mechanical switch. I don't mind crawling under the car to lock the transfer case - I would much rather that, than be at the mercy of some vacuum pipe and a diaphram in the middle of nowwhere, 100 miles from water!

I have checked, http://jubileejeeps.org/quadratrac/index.htm
but that does not answer all my questions, very good as it is though.

Thank you in anticipation.

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post #2 of Old 06-14-2013, 07:54 PM
lucdog
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1980 CJ5 
 
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Of the 3 lines, 1 is a vent for the TC.
If you have a low range unit on the TC it may be in netural.
Bill

1957 WILLYS pickup,
1973 J 4000,
1978 CJ7 DD.
1979 CJ7 360, TH400/Quadratrac.
1979 J20
1980 CJ5 trail Jeep.
1983 CJ7
1989 YJ the CJ to YJ.
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post #3 of Old 06-14-2013, 09:11 PM
pleontks
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You should have one small vacuum line coming from the engine to the switch, 2 small vacuum lines from the switch to the tcase. The other line off the tcase should be the vent, as lucdog said, ad much larger than the lines from the switch.

The clunk is normal (not so much good, but normal) and should be tranny engaging tcase.

If qtrac is not moving jeep at all, I would guess what lucdog said, that you have the low-range, and it's in neutral. Down is hi, up is lo. When putting mine into hi, half the time the handle hits the floor, and I think I'm i hi until I try to move, and nothing happens.

There's a cable shift kit available. Also, I think bjs offers a new switch.

Mine works fine after installing new lines.

As far as being stuck, it only uses the vacuum for the switching, not to hold it locked or unlocked. So, you can run vacuum to one of the spots on the tcase, locking it in, and then take it off, drive out, and hook it to the other to unlock.

Beauty is in the eye of the jeepowner.
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post #4 of Old 06-15-2013, 05:19 AM
lucdog
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1980 CJ5 
 
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The vacuum actuator can be tested using one of these

http://www.mityvac.com/pages/products_bcbe.asp
Just hook a line from the actuator to it and pump up some vacuum. You should then hear the actuator move, then connect the line to the other side and repeat.
The plus by doing it this way is no engine noise.

1957 WILLYS pickup,
1973 J 4000,
1978 CJ7 DD.
1979 CJ7 360, TH400/Quadratrac.
1979 J20
1980 CJ5 trail Jeep.
1983 CJ7
1989 YJ the CJ to YJ.
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post #5 of Old 06-15-2013, 06:53 PM Thread Starter
paulbone
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1977 FSJ Cherokee 
 
Join Date: Mar 2012
Location: las vegas
Posts: 22
Thanks very much guys for pointing in the right direction.

Turns out I'm a dummy! The TC was indeed in neutral. How the heck did the happen? It's only been sat in the garage while I swaped out the motor.

She now drives in all gears.

You guys really did save my sanity, thank you very much. Paul
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post #6 of Old 06-15-2013, 06:56 PM
lucdog
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Cool

B

1957 WILLYS pickup,
1973 J 4000,
1978 CJ7 DD.
1979 CJ7 360, TH400/Quadratrac.
1979 J20
1980 CJ5 trail Jeep.
1983 CJ7
1989 YJ the CJ to YJ.
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quadratrac , transfer case shifter


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