Merci! Enfin du concret!
Pouvez-vous m'expliquer un peu la procédure de réglage de la tringlerie de kickdown? Et aussi à peu près le temps que ça demande? (si je le fais faire, je ne veux pas me faire entuber!).
Je ne connaissais pas le shift kit, qui doit être utile en conduite sportive, mais pas très adapté à une conduite quotidienne. Comment peut-on vérifier sa présence, je suppose qu'il faut démonter? C'est facile à retirer le cas échéant?
Merci!

Merci, ce topic est très bien fait! ça explique le réglage d'une tringlerie de kickdown, mais à priori dans le cas de la 727 ça semble plus compliqué car ça gère la montée et la descente des vitesses! Depuis tout à l'heure, je fouine sur le net, j'ai trouvé ça:
"So, this is how a 727 decides when to shift: Attached to the output shaft of the transmission, just in front of the speedometer gear, is a unit called the 'governor'. It is centrifically sensitive. As driveshaft rpms go up the weights inside of the governor slide to the outside directing the pressure to two governor plugs, one for the 1-2 shift and the second for the 2-3 shift. This does two things 1) it decreases operating pressure so the clutches and bands hold with less force, and 2) it causes it to shift earlier allowing for your up-shift.

When you step down on the throttle hard, you are pushing a cam lever against a spool valve called a kickdown valve. It pushes on the throttle valve with some delay due to a spring between the two. The sliding of the kickdown valve allows throttle pressure to offset the governor pressure which delays the shift. Additionally, the movement of the throttle valve increases line pressure forcing firmer holding of the clutches and bands.

If you want to have a 727 shift earlier, you adjust the clearance of the kickdown cam on the side of the valve body. It is the upper arm whose shaft passes through the shift arm. If you remove the tranny pan and drain the fluid (Do this by removing most of the bolts on the tranny pan, leaving only a couple loose on one of the rear corners. This will focus the fluid so you can catch it in a pan easier.), you will see a sheet metal cage assembly with an allen or phillips headed screw that is screwed into the sheet metal. If you unscrew this screw a little ways, it will delay the engagement of the kickdown valve which will allow your tranny to shift earlier. The amount you turn the screw is measured in clearance between the cam and the kickdown valve.

In most shift kits that you purchase the suggested clearance between the cam lever backed all the way against the head of the screw and the kickdown valve's tip is 1/8 th inch. To measure this use the tail-end of an 1/8th inch drill bit as a feeler gauge. The photos show at my finger tip the gap that I'm talking about. Remember after you make any of these adjustments to the valve body you will have to re-adjust the kickdown rod to locate your desired shift point as I posted previously.

Do not be afraid to do this. Don't fear, you cannot hurt this thing. There's far too much mystical BS regarding transmissions!
Dommage, je n'ai pas eu accès aux photos.... Je continue à fouiner!