Re: 727 without Kickdown hooked up question
[Re: MrMayhem]
#2881802
01/29/21 05:58 PM
01/29/21 05:58 PM
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Joined: Mar 2009
Posts: 889 Oh
parksr5
super stock
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super stock
Joined: Mar 2009
Posts: 889
Oh
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I can answer one of your questions. The kick down linkage/ throttle pressure linkage being unhooked will cause damage.
Most make it sound like the transmission will burn up if you take it down the street without it being hooked up but, that has not been my experience.
I inherited my car and when I received it, the throttle linkage was not hooked up and hadn't been for probably 1500-2000 miles. Once I identified how important it is, I reinstalled and properly adjusted the linkage rather quickly.
Again, the car was not mine from the last time the trans was rebuilt up until shortly before I reinstalled the linkage. Over the time I owned and drove it without the linkage, I felt like I noticed low speed slippage getting worse. I also noticed that I had a flare between the 2-3 shift but, it wasn't horrible. My car too has an aftermarket converter and there were some other unknowns so; I didn't think much about it. I drove the car another 2-3 years before having the trans rebuilt and I only really had it gone through as I had the motor and trans out. Overall, the trans worked fine and I really only noticed the low speed slippage when I pulled it out of the garage and ran it down the first road. Once it got some heat in it, all seemed fine.
During the rebuild, we found the low/reverse band was burnt up. I want to say there were some other slight issues too but, it's been years so; I can't recall all the specifics.
With the trans rebuilt and reinstalled with the same converter, all the slipping at low speed was gone so; it was the band causing the weirdness I noticed. At the same time I had the trans rebuilt, I added around another 100 HP and 150 lbs of torque. The trans has been run with this combination for probably around 2000 miles and 25 or so passes and has never felt like it did before I had it rebuilt so; I would assume that the low/reverse band being burnt and the slippage I had in years past can probably be attributed to the kick down/throttle linkage being removed for all that time.
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Re: 727 without Kickdown hooked up question
[Re: MrMayhem]
#2881829
01/29/21 08:02 PM
01/29/21 08:02 PM
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Joined: Jan 2003
Posts: 12,294 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,294
Benton, IL.
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A few years back I acquired a 72 440/727 Plymouth Duster. The seller indicated the car had a manual valve body which I dont believe it actually does since the kickdown lever is still mounted on the trans. I have not drove the car much, maybe 2-300 miles but I have noticed the trans slipping between shifts the more I drive it. I have read somewhere if the trans kickdown in not functioning correctly or connected to the trans it will in fact damage the transmission. If this is accurate, what is being damaged and what is the remedy?
Another question, I was also informed the car has a High stall converter, maybe 2800 stall... The trans clearly slips at lower speeds if driving from a stop under light acceleration. If the pedal hits the floor, the tires blow smoke... I was under the impression that a good converter will not slip under light loads. Is that assumption correct?
Thanks First off: DO NOT DRIVE THE CAR WITHOUT KNOWING WHAT IS GOING ON WITH THE LINE PRESSURE. It can damage the tranny. What I mean by that is the kick down lever controls the pressure that is applied to the clutches and bands unless it has a manual valve body. If the valve body is not full manual, then the line pressure is at idle pressure all the time with the kick down lever not being tied to the throttle. A manual valve body puts the line pressure above even the normal wide open amount of pressure all the time. If it shifts on it's own at all, then it is not a manual valve body. There is a lot more to this, but that is enough until we get more information.
Master, again and still
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Re: 727 without Kickdown hooked up question
[Re: MrMayhem]
#2881851
01/29/21 09:07 PM
01/29/21 09:07 PM
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Joined: Aug 2003
Posts: 43,307 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,307
Bend,OR USA
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If you put it in drive and it shifts automatically it does NOT have a manual valve body it it won't shift by itself in any other gear it is a manual shifted tranny due to the valve body If it is NOT a manual valve body it will hurt and damage the tranny very quickly without the kick down linkage hooked up and adjusted properly The kickdown lever is used to hold the shift lever seal in place to stop it from weeping and or leaking around that shaft and the shift lever shaft is what I'm remembering now.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 727 without Kickdown hooked up question
[Re: Cab_Burge]
#2882006
01/30/21 12:18 PM
01/30/21 12:18 PM
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Joined: Nov 2020
Posts: 348 Isle of Sheeps
Gtxxjon
enthusiast
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enthusiast
Joined: Nov 2020
Posts: 348
Isle of Sheeps
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I’m amazed to see this still going on in the 21st Century! Before Lokar cable systems were available, setting up a mechanical kick down linkage was a pain. But still no excuse to leave it OFF. Most folks just wired it back, to almost fully open and suffered the harsh shifts! Too leave it dangling in the wind is criminal...
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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Re: 727 without Kickdown hooked up question
[Re: poorboy]
#2882277
01/31/21 04:20 AM
01/31/21 04:20 AM
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Joined: Dec 2013
Posts: 4,704 Wichita
GY3
master
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master
Joined: Dec 2013
Posts: 4,704
Wichita
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"Kickdown" is such a lousy name. It is really a variable line pressure mechanism. The more throttle you give it the more it increases the line pressure for the clutches to be pressed together harder. Without this line pressure increase under load, the clutches slip and burn up. The "remedy" is a rebuilt transmission.
Last edited by GY3; 01/31/21 04:21 AM.
'63 Dodge 330 11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs. 10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
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Re: 727 without Kickdown hooked up question
[Re: GY3]
#2882289
01/31/21 08:45 AM
01/31/21 08:45 AM
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Joined: Nov 2020
Posts: 348 Isle of Sheeps
Gtxxjon
enthusiast
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enthusiast
Joined: Nov 2020
Posts: 348
Isle of Sheeps
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Wow GY3, 10.01 @ 133 superb but so close to a NINE! Best we managed without Nos was 10.40 @ 130. I now see the errors of my ways and will be Nossing from now on lol...
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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Re: 727 without Kickdown hooked up question
[Re: Gtxxjon]
#2882316
01/31/21 10:45 AM
01/31/21 10:45 AM
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Joined: Dec 2013
Posts: 4,704 Wichita
GY3
master
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master
Joined: Dec 2013
Posts: 4,704
Wichita
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Wow GY3, 10.01 @ 133 superb but so close to a NINE! Best we managed without Nos was 10.40 @ 130. I now see the errors of my ways and will be Nossing from now on lol... Thanks. It's a very mild (and heavy) street car that see's some track time. It drives like a stock 440 with a cam.
'63 Dodge 330 11.19 @ 121 mph Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs. 10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
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