Tranny gurus later big block 727 part throttle kickdown

Posted By: KillerBee

Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:20 AM

I was talking to a tranny shop owner and he told me that the later model big block 727 transmission cases are better to build for street/strip applications (without using a full manual valve body), as the the newer cases have provisions for part throttle kick down instead of full throttle kickdown like the older big block 727.
I'm very ignorant about 727 trannys(I'm a 4 speed guy). Is this true?
What's the difference between the tranny cases?
What year cases are better?

Thanks.

Posted By: JohnRR

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:22 AM

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:23 AM

Quote:

UH OH did I open a can of worms?

Posted By: JohnRR

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:24 AM

Quote:

Quote:

UH OH did I open a can of worms?

No , I have a thought in my head but I'm keeping it to myself at the moment ...

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:31 AM

Quote:

I was talking to a tranny shop owner and he told me that the later model big block 727 transmission cases are better to build for street/strip applications (without using a full manual valve body), as the the newer cases have provisions for part throttle kick down instead of full throttle kickdown like the older big block 727.
I'm very ignorant about 727 trannys(I'm a 4 speed guy). Is this true?
What's the difference between the tranny cases?
What year cases are better?

Thanks.

Its the later valve body that is what he is talking about....parts from the later valve body can be used to help with shifting....

Its been years ..but I do remember reading this and useing it in a build up..... I am sure more exp trans guys can explain what it is that is diff..

All know it has to do with the later valve body 1-2 shift is better...when used in the earlier valve body it used to make shifting better...

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:34 AM

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Quote:

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UH OH did I open a can of worms?

No , I have a thought in my head but I'm keeping it to myself at the moment ...

I took the 727 tranny from my wife's 440 Sixpack powered 71 Challenger R/T in to have it gone through.
The tranny guy is very well versed in Mopars.
He said he had a later year 727 case he could use instead of the older(1969 I believe) case I took in.
i just wanted to get some opinions as to if it's a good idea.
The wife's Challenger is a street/strip car with much more street driving than strip passes.
I'm planning on using a Bouchillon kickdown linkage if that matters.

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:37 AM

He was able to determine it was an older, non partial throttle kickdown tranny just by looking at the side of the case where the linakge bolted to?

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:45 AM

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He was able to determine it was an older, non partial throttle kickdown tranny just by looking at the side of the case where the linakge bolted to?

yes but shifting has to do with the valve body not the case..............Possibly you mis understood him... I am trying to locate articale,,it was in Mopar Muscle years back.....

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 01:58 AM

this should help

http://www.allpar.com/mopar/transmissions/torqueflite-tom-hand.html

Posted By: John_Kunkel

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 09:19 PM

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He was able to determine it was an older, non partial throttle kickdown tranny just by looking at the side of the case where the linakge bolted to?

Correct, the location of the pipe plug on the accumulator (middle hump in case on passenger side) was changed on the later case; the plug is located low near the pan rail on the early case and up near the top of the hump on the later case.

There are pics of the two configurations in my 727 photo album:

http://community.webshots.com/album/563460286dArKFK

The first year for that change was '71 but not all got the change until a couple of years later. '71 was also the first year that the V8 got PTK and there were changes in the accumulator function that changed the case but the PTK function is in the valve body, not the case.

Posted By: dogdays

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 09:48 PM

Trading a possibly numbers-matching transmission case from an R/T for another case when the original case isn't broken would seem to be going backwards.

The part-throttle kickdown conversion was described by E-berg in Mopar Action a few years ago, it is a minor change to the valve body IIRC. Also isn't it true that a 904 valve body could give up the PTK valve?

R.

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 11:13 PM

Quote:

Trading a possibly numbers-matching transmission case from an R/T for another case when the original case isn't broken would seem to be going backwards.

The part-throttle kickdown conversion was described by E-berg in Mopar Action a few years ago, it is a minor change to the valve body IIRC. Also isn't it true that a 904 valve body could give up the PTK valve?

R.

I wasn't going to trade my case, (it's not original to the car) He was going to charge me $50 bucks extra to use his PTK case and give me my bare case back.

Thanks.

Posted By: John_Kunkel

Re: Tranny gurus later big block 727 part throttle kickdown - 08/27/08 11:52 PM

Once again, there is no "PTK case", it's all in the valve body.

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 12:29 AM

Quote:

Once again, there is no "PTK case", it's all in the valve body.

Thank You!!!

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 12:41 AM

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Once again, there is no "PTK case", it's all in the valve body.

Thank You!!!

So will the PTK specific valve body fit in all year 727 cases?

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 12:53 AM

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Quote:

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Once again, there is no "PTK case", it's all in the valve body.

Thank You!!!

So will the PTK specific valve body fit in all year 727 cases?

find this mag back issue

http://www.moparaction.com/Next/history/oct1989.html

http://www.moparaction.com/Next/history/feb1992.html

Posted By: KillerBee

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 12:57 AM

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Once again, there is no "PTK case", it's all in the valve body.

Thank You!!!

So will the PTK specific valve body fit in all year 727 cases?

find this mag back issue

http://www.moparaction.com/Next/history/oct1989.html

I found that earlier tonight.

I also read that A&A transmission supposedly has a PTK conversion kit?, what that would be I'll find out tomorrow.

Posted By: screamindriver

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 01:11 AM

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Also isn't it true that a 904 valve body could give up the PTK valve?

Yes..I've used one{from a 904} for the conversion after reading about that swap..

Posted By: Magnum

Re: Tranny gurus later big block 727 part throttle kick - 08/28/08 03:15 AM

For what it's worth. I feel the partial throttle is important in a slant six auto or a stock 318 with a 12 in convertor.
This upgrade with a 440 in front of it is just to say you have it. Big blocks accelerate just fine at partial throttle in high gear.

Posted By: JohnRR

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 04:02 AM

Quote:

Quote:

Quote:

UH OH did I open a can of worms?

No , I have a thought in my head but I'm keeping it to myself at the moment ...

The thought in my head is the same as others here , it's a function of the VB , not the case .

Posted By: cornucopia

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 12:43 PM

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Quote:

Quote:

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UH OH did I open a can of worms?

No , I have a thought in my head but I'm keeping it to myself at the moment ...

The thought in my head is the same as others here , it's a function of the VB , not the case .

and you don't even need the whole valve body to get the PTK...it's one small spool valve and a small, screw on housing. two screws and you can convert ANY valve body to PTK in less than 5 minutes. the slant six trannys got it first. around 1969 or so...I retrofit all my autos if they don't already have it.

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 01:55 PM

Quote:

Quote:

Quote:

Quote:

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UH OH did I open a can of worms?

No , I have a thought in my head but I'm keeping it to myself at the moment ...

The thought in my head is the same as others here , it's a function of the VB , not the case .

and you don't even need the whole valve body to get the PTK...it's one small spool valve and a small, screw on housing. two screws and you can convert ANY valve body to PTK in less than 5 minutes. the slant six trannys got it first. around 1969 or so...I retrofit all my autos if they don't already have it.

It all comes back to me now....LOL

Posted By: RapidRobert

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 02:43 PM

& FYI there was an article way back about 727 failures that was traced to mixing & matching shafts/gears as it seems there were slight changes in spline count or shape of the splines. Kunkel will know. It came down to there were(3) different groups of years in the 70's that the rotating assemblies must be kept together & not mixed & matched. this isn't directly related to the Q but something to be aware of.

Posted By: 340dart4spd

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 03:28 PM

Quote:

& FYI there was an article way back about 727 failures that was traced to mixing & matching shafts/gears as it seems there were slight changes in spline count or shape of the splines. Kunkel will know. It came down to there were(3) different groups of years in the 70's that the rotating assemblies must be kept together & not mixed & matched. this isn't directly related to the Q but something to be aware of.

I have had several built like this in the pas 20 years with no fail.....besides were not talking gears,were talking about a spring and a valve,that only affects the line pressure and shift point...

Posted By: RapidRobert

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 03:59 PM

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...besides were not talking gears,were talking about a spring and a valve,that only affects the line pressure and shift point...

Your comment contributed absolutely nothing techwise to this discussion. I did state that that my comments aren't directly related but something to be aware of as the trans shop MIGHT end up doing some mixing/matching & I wanted to possibly contribute something that give the OP as MUCH info as possible. I am going to try & find that article, Mopar Action I think.

Posted By: John_Kunkel

Re: Tranny gurus later big block 727 part throttle kickdown - 08/28/08 07:44 PM

The last post in the thread below has my rambling observations on the PTK retrofit:

https://board.moparts.org/ubbthreads/show...rue#Post4623468

Also, I would disagree that PTK isn't an asset to big block cars, while they may lug away in top gear just fine from low speed it's nice to have the more brisk acceleration of the lower gear.