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727 valve body question #2609262
01/20/19 11:30 AM
01/20/19 11:30 AM
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J Brough Offline OP
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Rebuilding the 727 from my 1970 Challenger R/T with a 383. It is a numbers matching transmission, but at some point in the past likely had work done on it since it was painted blue all over. I've never driven the car, so I have no idea if the trans functioned or not. Disassembled the valve body to clean it up. My intention is clean it up, inspect and put it back together. I found that instead of 5 - 1/4" check balls there were 4 and that the shuttle valve had a rod in it that blocked it from moving. Other than that the valve body does not appear to be modified in any way. Are these anomalies correct for a 70 valve body? If not should I reassemble it as it was or add the missing ball and remove the rod blocking the shuttle valve?

John Brough

Valve body check balls.jpgshuttle valve blocked.jpg
Re: 727 valve body question [Re: J Brough] #2609299
01/20/19 01:25 PM
01/20/19 01:25 PM
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lewtot184 Offline
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if IIRC turbo action had a shift kit like what you have. the separator plate may be different than stock also.

Re: 727 valve body question [Re: lewtot184] #2609335
01/20/19 02:51 PM
01/20/19 02:51 PM
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moparx Offline
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several different brands of shift kits back in the day had mods like the one's shown. does the transmission have the match on the numbers ? possibly, in it's lifetime, it was rebuilt and the kit was installed by the rebuilder.
beer

Re: 727 valve body question [Re: J Brough] #2609468
01/20/19 07:18 PM
01/20/19 07:18 PM
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John_Kunkel Offline
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Yeah, your VB has what is commonly called a "plate kit"; the steel separator plate is a one-size-fits-all, the missing 1/4" ball makes a harder 1-2 shift and blocking the shuttle valve makes the throttle-off upshifts way harsh.

Old school compared to a reprogramming kit.


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Re: 727 valve body question [Re: J Brough] #2609772
01/21/19 10:20 AM
01/21/19 10:20 AM
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Thanks for the insight. So to go back to stock I would need to find a separator plate, reinstall the ball and pull the blocking rod out of the shuttle valve. Getting the correct separator plate seems like the toughest find, since there were so many variations. If I removed the blocking rod to make off throttle upshifts less harsh and left everything else the same, would the trans function reasonably normally? I also did not find a spring on the accumulator nor was it blocked. Guess that too was part of someone trying to improve the shifting.

Thanks again for your help,

John

Re: 727 valve body question [Re: J Brough] #2609897
01/21/19 03:16 PM
01/21/19 03:16 PM
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John_Kunkel Offline
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If you toss the blocker rod (hopefully the spring is still in place) and install the missing ball it will likely have a little firmer 1-2 shift but act normally otherwise.


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Re: 727 valve body question [Re: J Brough] #2610030
01/21/19 07:55 PM
01/21/19 07:55 PM
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lewtot184 Offline
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if that is a turbo action shift kit then the separator plate won't allow for the use of the accumulator. it's missing a hole, which could be added if you knew the correct position. the best street driving valve body I've used was a later part throttle kickdown body with an early transgo shift kit.

Re: 727 valve body question [Re: J Brough] #2610322
01/22/19 10:19 AM
01/22/19 10:19 AM
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Yes, the spring is still in place in the shuttle valve, so removing the blocker rod is easy. Need to buy/find a ball, but that should not be hard either. Guess I'll make those changes and see how it works when I eventually get the car back on the road. Worst case is I might have to change out the valve body. Thanks again for your help.

John

Re: 727 valve body question [Re: J Brough] #2860316
12/15/20 02:44 PM
12/15/20 02:44 PM
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Gtxxjon Offline
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Hi John, it’s Limey John.

I just asked John K the same question on a different thread about the small blocker rod.
It was a race car VB so the harsh ‘no gas’ up change wasn’t an issue lol.

All the modern upgrade kits ‘remove that ball’ and drill the runner next to it, into the next chamber.
That is the wall to the right of where your black line ends...

Why or what this does is mystery as they don’t actually tell you?
That goes for B&M and transgo 1.


So just putting the 1/4 ball is stock.

Last edited by Gtxxjon; 12/15/20 02:47 PM.

Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
Re: 727 valve body question [Re: Gtxxjon] #2860323
12/15/20 02:59 PM
12/15/20 02:59 PM
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John_Kunkel Offline
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In a stock VB, the fluid that flows from the 1-2 shift valve to the 2-3 shift valve takes a rather circuitous path...it flows from the VB through the separator plate to the transfer plate then back through the separator plate to the VB. Removing the wall makes a direct path from one shift valve to the other....less parasitic flow loss.


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Re: 727 valve body question [Re: John_Kunkel] #2860736
12/16/20 01:16 PM
12/16/20 01:16 PM
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Gtxxjon Offline
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Hi John,

I knew you would KNOW!!! wave

Parasitic losses that's so cool...

Happy Christmas John and family.
(if that is even poss. these days)lol... beer beer drumhit


Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...






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