1969 TH400 transmission kickdown setup
 

Hi folks,
I have a 1969 CST/10 with a 350 engine, Quadrajet, and TH400 transmission. The kickdown mounts on the Quadrajet back left stud and is pressed with the original press lever that mounts on the throttle assembly. When this was on the truck before engine overhaul, I didn't get a picture and the overhauler chucked the kickdown and said "you don't need that." When I drove the truck to the transmission shop and had them overhaul the transmission, I asked them about the kickdown, and they said "you don't need that." A few years went by and I connected a 12V source to a light switch, and the other terminal on the light switch to the transmission, and took it for a test drive. When I floored the gas pedal, I simultaneously flipped the light switch. I concluded "I need that." So, I bought the kickdown switch from a forum member and now I'm installing it. This is what it looks like when idle and when full throttle. Does this look like the correct setup and correct action on the switch?

Re: 1969 TH400 transmission kickdown setup
 

Here's mine, on my '70, but just the side view.

Re: 1969 TH400 transmission kickdown setup
 

OK it looks like on yours the half-round cut out on the presser foot straddles the bottom unused hole instead of like I have it straddling the accelerator rod hole. I will see if mine fits better that way. It seems like the presser foot should hit the switch in a more straight-on way. Your switch looks quite different.

Re: 1969 TH400 transmission kickdown setup
 

Without looking at my build documentation photos, I believe the switch goes on top of the mounting bracket. That looks like it would solve your alignment issue if the actuator bracket was shaped different.

I am quite sure that's how I found it. Doesn't mean it's correct... I can't remember what that bracket looked like.

I'll look tonight.

Re: 1969 TH400 transmission kickdown setup
 

AFAIK, this is original. Though I know that when my FiL had the engine rebuilt, the rebuilder swapped sides with the heads, as the temp sender is on the passenger's side.

Re: 1969 TH400 transmission kickdown setup
 

My mistake. My switch was installed as yours is. I only have one photo of it installed and it doesn't show the entire setup. Just part of the throttle bracket is showing. I don't have one of what it looked like when the switch was engaged.

Sorry!

Re: 1969 TH400 transmission kickdown setup
 

OK, I went and checked switch activation on my truck. The foot, as installed, is flat to the switch pushrod at WOT, though the pushrod wipes across the surface of the foot while it strokes. It doesn't come at it straight on. It's been working for as long as I've known this truck, but I wonder if it is right. Found the page (401); looks like it's mounted wrong. And the switch I have does look like the one in the manual, except it doesn't have the boot.

OK, edited AGAIN! Looking back at your side view pic, the foot is tilted compared to mine. SBC to BBC maybe is the difference? Maybe I should delete my stuff- it may be red apples to green apples?

Re: 1969 TH400 transmission kickdown setup
 

OK the majority I see seem to be half-round cut-out on the presser foot straddles the bottom unused hole and that puts it at an angle such that the presser foot wipes across the switch button and ends up fairly flat on the button when fully engaged. In addition to the pictures from this thread, this picture from FirstOwner69 seems set up that way. https://67-72chevytrucks.com/vboard/...1&d=1528394702

So, I set up mine like this. I think it's going to be fine, and Steeveedee I think yours is fine. My engine builder and my transmission shop would say you don't need that. I put a little grease on the presser foot. I'm going to get around to replacing the stretched-out throttle return spring and connect it so it pulls from the water neck, then I will connect the switch electrically to the transmission and switched ignition-on power source. Thank you everybody for your responses.

Re: 1969 TH400 transmission kickdown setup
 

I think page 401 of the assembly manual is just showing the switch flipped on its side to make the wiring clear, and it's just a sketch. There's other imaginary stuff there in the illustrations, such as the fuse box terminal next to the radio terminal as a place to plug in. There's no terminal there.

Re: 1969 TH400 transmission kickdown setup
 

I think that you are right. I've made many drawings to ASME and ANSI and DoD standards so when I look at this stuff in the assembly manual I get confused. I'd expect better section views, but our trucks aren't spacecraft. :lol: Your "foot" looks just like mine at WOT, on the switch. Ain't rocket science, I guess. And yeah, I was thinking about some lube on that interface. I'll bet that the lube guy at the dealer had a list of things to lubricate. When I worked as a mechanic (not at a dealer), if I noticed a squeak, I would lube it.

Re: 1969 TH400 transmission kickdown setup
 

Do any of these help?

Re: 1969 TH400 transmission kickdown setup
 

Yes and thanks Jim, that is very clear.

Re: 1969 TH400 transmission kickdown setup
 

You're welcome. Glad I could help.