does anybody know what this is?

[Jbreeeeeeeeew]

The contraption is out of a 1973 gmc c1500 with a 454 and it goes on the pedal bracket or it is the pedal bracket. In lmc its says its on a 74 thru 89 but mines a 73 idk if its some sort of a cruise or kickdown or even a governor. Lmc dosent say nor sell it but it has a picture. Thanks for viewing

 

[RetroC10Sport]

Turbo 400 kickdown switch.

 

[Swims350]

x2 exact thing I thought of.

 

[Jbreeeeeeeeew]

But why would it be on my 73 when in lmc says its made for a 74 thru 89

 

[HotRodPC]

LMC must be wrong, or could be a retrofit design, or someone else swapped it in. It may be that for 73, GM used a Carbed activated switch and 74 up used the pedal switch. Good luck finding a carb switch. Someone could have swapped it. The 1 tons did get a Th400, but I believe it's up 76, maybe 77, even 3/4 tons got Th350. Then GM went with Th400's in the 3/4 tons after that, so unless your truck was a 1 ton, it had a Th350 originally, which makes me think somone may have converted it to Th400 and added the provision for the kickdown switch.

 

[HotRodPC]

I now see your truck is a 73 1/2 ton with a 454??? IIRC, 454 was not an engine option for a half ton in 73. That tells me your motor and trans were swapped in, and someone also retrofitted the pedal switch from a later model 3/4 or 1 ton truck.

 

[Jbreeeeeeeeew]

In 1973 the 454 was most definitely an option I have to original receipt and it was purchased in april of 73 with the 454 cid option so no niether the engine nor tranny where swapped in

it has a stock th400 and 454 well I mean it came in the truck in 73 the engines fairly stock but getting back to the original question I dont have a kickdown on my new edelbrock so is this the kickdowm?

 

[RetroC10Sport]

I now see your truck is a 73 1/2 ton with a 454??? IIRC, 454 was not an engine option for a half ton in 73. That tells me your motor and trans were swapped in, and someone also retrofitted the pedal switch from a later model 3/4 or 1 ton truck.

Yes it was old man! We actually have a couple of members with factory 454 half tons, SlickGTP comes to mind.

 

[Tyger13us]

In 1973 the 454 was most definitely an option I have to original receipt and it was purchased in april of 73 with the 454 cid option so no niether the engine nor tranny where swapped in

it has a stock th400 and 454 well I mean it came in the truck in 73 the engines fairly stock but getting back to the original question I dont have a kickdown on my new edelbrock so is this the kickdowm?

yes ya need it for the th400.....

 

[Jbreeeeeeeeew]

So is my truck rare with a factory 454


what do I need to buy to get the kickdown to work properly or do I even need a kickdown its a daily driver for my 16 year old son and its fast now I dont wanna know what it will be like when it downshifts

 

[RetroC10Sport]

Not exactly rare but rather uncommon we shall say.

You need the kickdown or you will have a burned up trans in short order. Looks like you have everything but the wiring harness.

 

[Jbreeeeeeeeew]

Something plugs in to that part pictured above under the dash and the same colored wiring goes to something on the side of the tranny. I will actually track it down when the weather gets below 105 here in Texas

So theres nothing on the carb just wiring that goes from pedal to tranny

 

[RetroC10Sport]

Well then, there you are. And yeah, I hear you on the heat. I'm headed to the junkyard early tomorrow so I can hopefully get my stuff and be gone before it hits 100.

 

[chengny]

Yes, that is the "detent switch". It is what activates the detent solenoid.

When the detent solenoid is energized (by the accelerator linkage closing the detent switch) a 3-2 downshift occurs - at speeds less than 70 mph.

At lower speeds, downshifts will occur at lesser throttle openings without the use of the electric switch.

BTW - other than the hassle of not having an automatic downshift at WOT - don't stress about not having a kickdown function. Contrary to popular belief, a non-functioning detent solenoid will not cause any harm to the transmission.

It is a simple normally open switch supplied with 12 VDC (the source is not important any convenient IGN switched circuit will work).

When the gas pedal is depressed a certain distance - close to the WOT position - the linkage arm closes the switch and power is sent to the detent solenoid via an orange wire.

The orange wire penetrates the firewall , runs down the RH side of the TH400 casing, passes through the casing at a rubber gland and terminates at the solenoid:

 

[Jbreeeeeeeeew]

Thanks ill go test it tomorrow if ya know what I mean and that does look familiar so I think its hooked up.

And yes I wish there where junkyards in the fort worth area ive been down junkyard road and no one has square bodies!!!!