lps&vettes

Ok, I have adjusted the kickdown cable on a TH350, but don't see one on the TH400. What is the procedure for adjusting the kickdown? When I nail it, the secondaries open, but it won't kick down.
Thanks!
Todd

TXShark

I think there is an electric switch under the dash that makes it kick down. There may be adjustment there.

7t2vette

The TH-400 doesn't have a cable for kick down, instead there is an electrical switch activated by the gas peddle. You can adjust it by pulling the switch out all the way and then putting the gas peddle to the floor "setting" the kick down position. To test if it is set right, turn the ignition on without starting the engine, and press the gas to the floor, you should hear a "click" from the tranny.

Steve's74

The kickdown on a Turbo 400 is controlled electrically by a switch on the gas pedal. There isn't much adjustment, so you likely have an inactive electrical circuit that needs to be diagnosed.

Steve

:edit:
Same time posts!

Sarge81

'68-'72 THM-400 Detent switch is located on the carburetor.
'73-'77 THM-400 " " " " over the accelerator.

Just a little FYI on the differences.

lps&vettes

Cool, thanks. Where on the carb? Mine's a ' 72 and the only thing I can see is the TCS solenoid. Am I looking in the wrong place?

7t2vette

The switch is on the gas peddle on a 72, the years are wrong on the other post.

lps&vettes

7T2vette,
Thanks for the straight skinny. Tomorrow I will adjust as described and post results on Tuesday.

Todd

Sarge81

I guess the Chilton's manual is wrong. Sorry bout that.

Swamper

I have a 69 L-68 W/ Th400 and the detent switch is above the gas pedal. To adjust it there is a small hole in the right side of the switch that is actuated by the pedal. Depress the pedal fully and move the switch on it's mounting bracket until the holes line up between the plunger and the housing and the switch. You need to insert a small pin, I used a long allen wrench, to check allignment. I have exact instructions somewhere, I'll keep looking.... Also, there is a vaccum line that comes off the intake that supplies power to the servo (I think). Make sure the vaccum line is intact as well. When I did mine I used a test light at the pedal switch and the had a helper mash the pedal while I tested it at the transmission ( with the ignition on and engine off of course ) I'll see if I can find the manual, my memory fails me at times. Swamper

carhound

I have a 69. It's kickdown switch is above the gas pedal. I could not find a switch for mine at any of the vendors or trans. shops. What I finally done was to go to NAPA and had them to order a switch for a Subaru (I think an 82-85) or something like that, It is a pushbutton type. It mounts on the carb. I make a bracket and attatched it to it and ran the wires from the original switch wires to the new switch, and it works like a charm. You may be able to find one for your model, but in case you can't, I just thought I let you know of another way to go.

lps&vettes

Carhound,
Thanks for the alternative. If the original switch is dead, that will be good to know!
Todd

RonR80

My 70 is on the gas pedal also , and thanks for the info mine is not working , I'll have a look at it .

Primoz

My 71 also has electrical switch at the gas pedal assembly!
I noticed it when I changed the throttle cable and guess what, I also have a problem with kickdown when I floor it!
I will try the adjustments as well and report back!

https://willcoxcorvette.com/corvette...ownshift-70-77

bigvette1

Sarge 81, would you have a diagram of the mounting of the switch on the carb for the 68-72 as I have a 73 and the switch does not want to stay adjusted, crawling under the dash is a chore for a large person. Thanks

Jim
dbc340parks@aol.com

jef602

What controls the cowl induction hood on 73 to 75 ? Or is the gas pedal switch control both?

'75

Pedal switch controls both.

Primoz

Today I tested the kickdown switch and there was no click from heard and during driving kickdown doesn't work either!
My car is a 71 with 350 and th400!

RonR80

Primo , have a look at the wiring under the car left side of tranny , mine was all burnt, I repaired the 2 wires and tested the switch on the pedal and it clicked , test drove the car and it works , I did the adjustment on the pedal with my fingers to see if it moved ok .

69Vett

must have 12volts feeding switch.