Issue with transmission
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,151
Likes: 294
From: Opelousas, Lousiana
CI 6-7 & 9 Veteran
Issue with transmission
I have a stock 72 350 Automatic. When I first got it, the linkage needed adjustment and the rear two bbls of the quadrajet would not engage. I have fixed that issue, bit now I notice that when I punch it the transmission does not downshift as it should. The transmission works flawlessly in every other way. It was rebuilt in 2009 and has only had about 2500 miles on it since and has been regularly serviced.
Any ideas what could cause this?
Any ideas what could cause this?
Race Director
Joined: May 2006
Posts: 18,662
Likes: 2,563
Assuming you have the original transmission it is the Turbo 400 or M40 and has a kickdown switched located on the gas pedal linkage under the dash. Check to see if the wire connector came off to start with.
You also may want to give some more detail as to what you actually did to the throttle linkage.
You also may want to give some more detail as to what you actually did to the throttle linkage.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
Once you locate the kickdown switch, you will see that it must be pushed by the top of the pedal arm to actuate it. You can reset the switch by pushing the part that contacts the pedal rod forward, this will reset the switch so that next time you floor it, the switch will self adjust.
Race Director
Joined: Mar 2003
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From: Eustis ( Area 51 Bat Cave ) Fl
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Race Director
Joined: Apr 2009
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From: Charlotte NC
I have to politely disagree...becasue this does not always work. I have reset the switches many times...and it does not work...and by slipping a hose onto the switch shaft...it worked perfectly.
Because when I did go and replace the switch and it still did not want to work...and it needed a little bit more throw...I have learned to slip on a hose and see if that does it if resitting it does not get it to work.
And this is also taking into account if the car has floor mats. I often times have to remove the accelerator pedal and bend it so I get full throttle due to some floor mats keep the carb from full throttle...and I do not like pressing on the gas pedal so hard that I feel I am going to push it through the floor. BUT...regardless of any accelerator pedal modification...the switch only needed a hose many times.
DUB
Because when I did go and replace the switch and it still did not want to work...and it needed a little bit more throw...I have learned to slip on a hose and see if that does it if resitting it does not get it to work.
And this is also taking into account if the car has floor mats. I often times have to remove the accelerator pedal and bend it so I get full throttle due to some floor mats keep the carb from full throttle...and I do not like pressing on the gas pedal so hard that I feel I am going to push it through the floor. BUT...regardless of any accelerator pedal modification...the switch only needed a hose many times.
DUB
Last edited by DUB; Feb 3, 2017 at 06:47 PM.
Race Director
Joined: Mar 2003
Posts: 11,608
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From: Eustis ( Area 51 Bat Cave ) Fl
For clarifying my situation, My 69 at one time had a blower sticking out the hood, the long Cable for it i replaced with a slick after market cable the correct length, at that time i made sure i didnt have anything like carpet under the pedal restricting it and that i had full carb opening...i heard that trick for i am guessing over 35 years about resetting kick down and it takes force, my dad rip would poke fun saying the kick down on his avanti with th400 was an easy to get at spring loaded toggle on the outer firewall..but end the end with mine sure brackets could be bent pedals tweaked but the reset wouldnt take and a piece of hose fixed it which is a somewhat common fix.
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 3,151
Likes: 294
From: Opelousas, Lousiana
CI 6-7 & 9 Veteran
Actually, I did not do it a Corvette Specialty shop did it. He removed the intake manifold (and actually pulled the engine for other work) to replace the gasket and when he put it back together, he adjusted the carb linkage.
Assuming you have the original transmission it is the Turbo 400 or M40 and has a kickdown switched located on the gas pedal linkage under the dash. Check to see if the wire connector came off to start with.
You also may want to give some more detail as to what you actually did to the throttle linkage.
You also may want to give some more detail as to what you actually did to the throttle linkage.