1970 th400 downshift solenoid questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

406cid70Chevy · 06-06-2004, 04:31 PM

The downshift solenoid is in the transmission but no wire is hooked up to it so I have no clue where the wire should go. In 1970 C20's with the th400 was there a switch on the gas pedal that indicated throttle postion or was it on the carb? Here's a pic of a 71-72 gas pedal assembly, should I have this in mine, because I don't.

**john** · 06-06-2004, 04:40 PM

I don't have a pic but it was on the carb. John

406cid70Chevy · 06-06-2004, 05:28 PM

Did the wire just plug in somewhere on the carb and that's it, or is there more to it?

I don't have a detent cable either, did these trannys(th400) come with one in '70?

neonlarry · 06-06-2004, 05:58 PM

Quote from another website:
"The TH400 uses an electrical slide switch, which is controlled by the throttle linkage."
Advert with pic for Hurst kickdown switch.
http://www.firewheelclassics.com/det...duct_id=TRN605

**Classic Heartbeat** · 06-06-2004, 06:19 PM

You have to have a wire running to ignition unfused also. The stock set up has a wire that plugs into the cigarette lighter spot. Then it has a pig tail that the T-400 switch plugs into. The front spade on the kick-down switch goes to the transmission and the rear spade goes to the 12 volt soarce. WES www.ClassicHeartbeat.com

406cid70Chevy · 06-06-2004, 07:01 PM

Quote:

Originally Posted by WES

You have to have a wire running to ignition unfused also. The stock set up has a wire that plugs into the cigarette lighter spot. Then it has a pig tail that the T-400 switch plugs into. The front spade on the kick-down switch goes to the transmission and the rear spade goes to the 12 volt soarce. WES www.ClassicHeartbeat.com

I still have the pig tail in the cigarette lighter spot. So, all I need is a wire that runs from the kickdown switch to the pigtail, right? I already have my 12 volt ignition wire in the ign. unfused slot. Here's a pic of from what I understand how it should hook up.

JimKshortstep4x4 · 06-06-2004, 09:10 PM

Here is a picture of what the 70 and older kickdown switch looks like.

Jim

**Classic Heartbeat** · 06-06-2004, 10:44 PM

If you look at the picture of your kick down switch next to the carburetor. The 2 plugs that you have yellow wires going to, the one front (closest to radiator) runs down to the transmission. The one in the rear (closest to the firewall) runs to the extra plug in the pig tail for your cigarette lighter. WES www.ClassicHeartbeat.com

**Classic Heartbeat** · 06-06-2004, 10:58 PM

Lets see if this worked..

406cid70Chevy · 06-07-2004, 12:03 AM

Ok I gotcha. Thanks for all the help guys.

JimKshortstep4x4 · 06-07-2004, 06:28 AM

Hey WES,

Good job!

Jim

**Classic Heartbeat** · 06-07-2004, 11:32 AM

Yuor welcome 406cid70Chevy...

And thank you JimKshortstep4x4.. WES www.ClassicHeartbeat.com

**COBALT** · 06-07-2004, 01:22 PM

You can get aftermarket switches for newer carbs buy the way. Basically the same concept (provide 12v to solenoid when throttle is near WOT). I use the Lokar one on my Edelbrock 1406. Pretty slick.

06-06-2004, 04:31 PM	#1
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	1970 th400 downshift solenoid questions The downshift solenoid is in the transmission but no wire is hooked up to it so I have no clue where the wire should go. In 1970 C20's with the th400 was there a switch on the gas pedal that indicated throttle postion or was it on the carb? Here's a pic of a 71-72 gas pedal assembly, should I have this in mine, because I don't.

06-06-2004, 04:40 PM	#2
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	I don't have a pic but it was on the carb. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

06-06-2004, 05:28 PM	#3
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	Did the wire just plug in somewhere on the carb and that's it, or is there more to it? I don't have a detent cable either, did these trannys(th400) come with one in '70? Last edited by 406cid70Chevy; 06-06-2004 at 05:41 PM.

06-06-2004, 05:58 PM	#4
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Quote from another website: "The TH400 uses an electrical slide switch, which is controlled by the throttle linkage." Advert with pic for Hurst kickdown switch. http://www.firewheelclassics.com/det...duct_id=TRN605 __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

06-06-2004, 06:19 PM	#5
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,768	You have to have a wire running to ignition unfused also. The stock set up has a wire that plugs into the cigarette lighter spot. Then it has a pig tail that the T-400 switch plugs into. The front spade on the kick-down switch goes to the transmission and the rear spade goes to the 12 volt soarce. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

06-06-2004, 09:10 PM	#7
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Here is a picture of what the 70 and older kickdown switch looks like. Jim Attached Images

06-06-2004, 10:44 PM	#8
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,768	If you look at the picture of your kick down switch next to the carburetor. The 2 plugs that you have yellow wires going to, the one front (closest to radiator) runs down to the transmission. The one in the rear (closest to the firewall) runs to the extra plug in the pig tail for your cigarette lighter. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

06-06-2004, 10:58 PM	#9
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,768	Lets see if this worked.. __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys Last edited by Classic Heartbeat; 10-04-2007 at 07:17 PM.

06-07-2004, 12:03 AM	#10
406cid70Chevy Registered User Join Date: Nov 2002 Posts: 43	Ok I gotcha. Thanks for all the help guys.

06-07-2004, 06:28 AM	#11
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Hey WES, Good job! Jim

06-07-2004, 11:32 AM	#12
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,768	Yuor welcome 406cid70Chevy... And thank you JimKshortstep4x4.. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

06-07-2004, 01:22 PM	#13
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	You can get aftermarket switches for newer carbs buy the way. Basically the same concept (provide 12v to solenoid when throttle is near WOT). I use the Lokar one on my Edelbrock 1406. Pretty slick. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.



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