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Discussion Starter #1
Hutch i was wondering if you or anyone else has had expierence with a th400 behind a mild cummins 6bt i plan on swapping into my dually. What to do about shift modulater, governer, etc. I did see that tci makes a convertor just for this combo as well as a low gear engine brake valve body. I am also aware of transmission connections makes a bellhousing adapter and flex plate combo for this. Thanks for any info. Chime in.
 

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My dad did one in a 87 chev dually with a turbo 400 with a gear vendor overdrive. The mechanical modulator we couldn't get to work so he went with a manual valve body. I can't remember the name of the company that made the adapter , but I'll get it for you. I think it used a ford starter on the passenger side. The proplem with that was the down pipe ...it made it really tight. I would see if you could get something to work on the drivers side like the cummins originally had. I'll get you some more info.
 

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Discussion Starter #3
Thanks twotontird, i appreciate it.
 

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They work just fine but you will have to use a mechanical modulator valve setup or come up with a false vacuum signal that follows throttle position and boost.


Hutch
 

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Discussion Starter #5
Hutch, according to the tci website that valve body is a manuel shift type. So correct me if im wrong but wouldnt that eliminate the need for a shift modulater and the governer. Just need a low stall speed convertor, also is there any thing you would have to do to the front pump due to the low engine rpm. Thanks for the info hutch.
 

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If this is a street driver you may want a manual valve body with engine braking in 2nd and 1st. Most are PRN321 stock shift pattern...
 

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the converter made for your cummins is called a allison 290 it was used in diesel powered motor homes with the allison 545 good luck. don't believe the folks that say they can make one, they can not unless they have a 290 core
 

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Discussion Starter #9
thanks for the info fellas. Isnt a allison at545 just a heavier glorified 400 with a 4th gear?
 

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Discussion Starter #11
and no park pawl.
You sure you want a manual valve body on a daily driver?

I thought about it really is no different than shifting a manuel trans. I only drive 7 miles to work and 11 miles to the track. With the occasional trips to quaker city or norwalk. I dont really drive the truck everyday, fair weather only.
 

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YES SORT OF JUST.
1ST,2ND AND 3RD CLUTCH IS 10 TIMES THE SIZE OF A T400.
AS FOR THE REST VERY MUCH THE SAME,DESIGNED BY GM-ALLISON ALL PART OF SAME COMPANY,IN THE GLOBAL SCHEME OF THINGS.
GREAT TRANS WOULD MAKE A SUPER RELIABLE 4 SPEED PITY ABOUT THE WEIGHT FACTOR IN A DRAG CAR

WE USED TO MOD THEM TO A POWER-SHIFTS TRANS,FOR MINE WORK ESPECIALLY FOR THE INDOSESIA OPERATORS.
 

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Mikie, if you look at Brains truck again his 6bt has a vacuum pump on it so all you need to do is run a hose to the modulator valve .

Bigtime we have a friend that has a 79 Chevy 4wd duallie with a Cummins 6bt in it and it fits in there like a glove and getting 20 miles to a gallon he has a 5 speed in his
 

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Mikie, if you look at Brains truck again his 6bt has a vacuum pump on it so all you need to do is run a hose to the modulator valve .

Bigtime we have a friend that has a 79 Chevy 4wd duallie with a Cummins 6bt in it and it fits in there like a glove and getting 20 miles to a gallon he has a 5 speed in his
You can't just run a vacuum hose from the vacuum pump to the modulator. The vacuum must be regulated by throttel opening or the transmission will not work properly.
If you hook the vacuum hose directly from the pump to the modulator, the line pressure will be way too low and will toast the transmission.
 
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