1979 Jeep CJ7 Turbo 400 problems

Tiny
ASTRATTMAN
  • MEMBER
  • 1979 JEEP CJ7
Transmission problem
1979 Jeep CJ7 6 cyl Four Wheel Drive Automatic

I just finished installing a rebuilt transmission and overhauling my transfer case, due to slipping gears. The transmission would engage and then as it warmed up would not engage any gears no matter of RPM. The rebuilt transmission does not engage at all, in any gear. If the transfer case is in neutral and I park the transmission there is a dull clicking sound that slowly stops. But that is the only evidence the linkage is working properly. I did not change the torque converter. Also, I had to change the output shaft so it would match my transfer case, but the process seemed simple and straight forward after disassembling the old trany, disassembling the new and reassembling with the old output shaft. The rebuilt transmission also had a shift kit installed. Any ideas why the transmission is not engaging. Torque converter. Valve body. Shift kit?
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Tuesday, May 13th, 2008 AT 3:09 PM

4 Replies

Tiny
JACK42
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Could be the converter, they should always be replaced when rebuilding a trans, they can carry debris that will hurt the new trans. Did a shop rebuild the trans? Did you check the t-case to see if it worked properly before you re-installed it?
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Wednesday, May 14th, 2008 AT 12:48 PM
Tiny
ASTRATTMAN
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After looking through a T-400 book, it seems that my problem may be that the pressure regluator is stuck in the pump. I was told the pump was new when the trans was rebuilt, but it was a few years ago.

I have tested the Dana 20 t-case and it seems to be working properly.

The transmission had been professionally rebuilt, however, I did the output shaft swap myself. A tranny shop did the final seating of the pump and everything seemd to be correct, but regretablly I did not have them dyno test it.

Aside from the issue of debris, if the converter is faulty could it be the cause of zero engagement in all gears if it worked before? I added a quart of fluid to the converter before install, but quite a bit leaked from the cooling line fitting before the lines were reconnected. Could there be an air lock in the cooling lines?
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Wednesday, May 14th, 2008 AT 1:31 PM
Tiny
JACK42
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Unlikely, the fluid level is correct though? Yes a broken/failed converter can make a no engagement situation. Might need to be sure you got the output shaft in right
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Thursday, May 15th, 2008 AT 7:44 AM
Tiny
ASTRATTMAN
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At the risk of sounding kind of stupid. The problem was the linkage to the main valve was not indexed. Once the linkage was actually connected to the valve, the tranny worked great. Now if someone asks why their tranny is not engaging at all, have them check the main valve linkage!
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Monday, May 19th, 2008 AT 11:06 AM

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