moran75 Posted August 20, 2019 Share Posted August 20, 2019 Hi All Just for my own education re. kickdown solenoid on my 65 Riv TH400... I know its activation causes downshift at speeds below 70mph...but how is this actually activated? I've attached two pics ..the original style solenoid covers an 'empty' hole but ....physically doesn't touch it because of the gasket...in my ignorance i was expecting some kind of plunger to shoot out and interrupt movement of the ATF, but there is only a small hole that also isnt quite centered in the opening in the gasket..... So what happens when it clicks to make the downshift happen? An (educated?) guess by me - the activation of the solenoid energises the metal gasket which in turn transfers the 12V to the body of the transmission ,,,and somewhere down the line changes route of ATF... Enlightenment very welcome... Many thanks Kevin Link to comment Share on other sites More sharing options...
PWB Posted August 20, 2019 Share Posted August 20, 2019 (edited) 14 minutes ago, moran75 said: Hi All Just for my own education re. kickdown solenoid on my 65 Riv TH400... I know its activation causes downshift at speeds below 70mph...but how is this actually activated? I've attached two pics ..the original style solenoid covers an 'empty' hole but ....physically doesn't touch it because of the gasket...in my ignorance i was expecting some kind of plunger to shoot out and interrupt movement of the ATF, but there is only a small hole that also isnt quite centered in the opening in the gasket..... So what happens when it clicks to make the downshift happen? An (educated?) guess by me - the activation of the solenoid energises the metal gasket which in turn transfers the 12V to the body of the transmission ,,,and somewhere down the line changes route of ATF... Enlightenment very welcome... Many thanks Kevin This link should provide answers: http://www.buickperformanceclub.com/SPTrans.htm Was your tranny ever overhauled? Edited August 20, 2019 by PWB (see edit history) Link to comment Share on other sites More sharing options...
moran75 Posted August 20, 2019 Author Share Posted August 20, 2019 Hi Paul Thanks for getting back to me so quick. Don't know if its been overhauled in the past . ... the wiring for the switch pitch solenoid is still there and clicking so i'm assuming it at least hasn't been converted to Fixed pitch as the article suggests sometimes happens... As i'm very much on a learning curve the article is a bit hard to follow.. But.... So kick down kick down is achieved by 'DET pressure' acting on a '1-2 detent valve'... As you asked if the trans was rebuilt does that suggest the detent vale is missing and should be poking through the empty hole as evidenced in my first pic? Or am i barking up wrong tree?! All the best Kev 17 minutes ago, PWB said: This link should provide answers: http://www.buickperformanceclub.com/SPTrans.htm Was your tranny ever overhauled? Link to comment Share on other sites More sharing options...
moran75 Posted August 20, 2019 Author Share Posted August 20, 2019 1 hour ago, PWB said: This link should provide answers: http://www.buickperformanceclub.com/SPTrans.htm Was your tranny ever overhauled? let me amend my last comment - so rfurther esearch suggests the 1-2 valve doesn't actually physically hang through the hole (pic 1) as I proposed a moment ago ..instead maybe veactivation of solenoid results in 'DET pressure' which acts on the 1 2 valve up in the valve body? So back to the hole in pic 1 - how does the DET pressure get created? by a vacuum created when the solenoid is activated? Thanks in advance KEvin Link to comment Share on other sites More sharing options...
PWB Posted August 20, 2019 Share Posted August 20, 2019 I'm no transmission expert but I would assume that hole is metering fluid by design. I would want to make sure all the right stuff was put back in if you desired full switch pitch action. Thats why I asked about its history and posted the link. Perhaps a tranny expert might can chime in. The Buick Performance boys might help - in their forum. Link to comment Share on other sites More sharing options...
moran75 Posted August 20, 2019 Author Share Posted August 20, 2019 many thanks..much more en-lighened then when i started! Kev Link to comment Share on other sites More sharing options...
psychostang Posted August 20, 2019 Share Posted August 20, 2019 Both internal solenoids for kickdown and swith pitch simply port fluid pressure, to the respective valve body and torque converter. Link to comment Share on other sites More sharing options...
moran75 Posted August 20, 2019 Author Share Posted August 20, 2019 27 minutes ago, psychostang said: Both internal solenoids for kickdown and swith pitch simply port fluid pressure, to the respective valve body and torque converter. so.....when solenoid activates it briefly 'seals' the above chamber, thus changing fluid pressure etc?.. Cheers Kev Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now