electrical terminal on the side of a TH350 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikep · 01-24-2003, 11:28 PM

I'm about to install a TH 350 in my truck. Its been a while since I have dealt with one of these but there is a eletrical terminal on the side . What is it? Isnt the Neutral safety switch built into the shifter or is that just on console shift models. I dont remember seeing one on the transmission itself.

383 Stroker · 01-25-2003, 12:44 AM

The TH350C has a electrical connection for the lockup converter.

*rustedchevy* · 01-25-2003, 12:53 AM

you have to remember that soem th350 were C models and others were not

Longhorn Man · 01-25-2003, 01:45 AM

Mike, are you 100% sure it is a TH350 and not a 400?

da-burb · 01-25-2003, 01:56 AM

Some of them will have a plug in on the passenger side. Is that the one you are talking about? If it is, then it is part of the emissions control. It's a temp switch that partly controls the vacuum solenoid. You won't need it so your best bet is to plug it.

mikep · 01-25-2003, 02:23 AM

Bingo ! Thats what it is. Its a temp switch. Its on the passenger side just behind the kick down cable. It looks just like a water temperature sensor with one male 1/4" spade terminal . I had the valve body apart and I know its not a lockup model. Yep. Temp switch. Thanks for the help!

mikep · 01-25-2003, 04:04 AM

Nah thats not it. Its a pressure switch. Its like the oil pressure sensor. You know. The kind like you find on a small block with an electric oil pressure gage or an idiot light. Its got 1/8" NPT threads and a 1" hex head with a single male spade terminal. Now I am confused. Its not a solenoid like youd find with a lockup . What is this thing. It's probably emissions related but what does it do?

Blazer1970 · 01-25-2003, 09:34 AM

If it is for the TCS system that came stock on these trucks, it is a high gear indicator. I have never seen one in person, but if it is a pressure switch like you say, then it must detect the pressure in the third gear clutch hydraulic circuit to indicate that the tranny is in third gear. The TCS system also uses a relay (mounted on the vacuum canister on the firewall), a vacuum solenoid in line between the carb and the distributor, and a temperature switch on the engine. Unless all this stuff is hooked up and working, you can ignore the switch on the tranny.

mrein3 · 01-25-2003, 12:27 PM

I removed that switch and replaced it with the sender for my Autometer transmission temperature gauge.

mikep · 01-25-2003, 01:01 PM

Thats it. Got to be TCS. It came out of a 72 1/2 ton so that makes sense. Might be the good basis for a hi speed ignition retard setup for drag racing....hmmmm.

01-24-2003, 11:28 PM	#1
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	electrical terminal on the side of a TH350 I'm about to install a TH 350 in my truck. Its been a while since I have dealt with one of these but there is a eletrical terminal on the side . What is it? Isnt the Neutral safety switch built into the shifter or is that just on console shift models. I dont remember seeing one on the transmission itself. __________________ No truck :-(

01-25-2003, 12:44 AM	#2
383 Stroker Registered User Join Date: Aug 2001 Location: Jesup, GA Posts: 571	The TH350C has a electrical connection for the lockup converter. __________________ Video's of my Truck Racing 1967 C-10, 383ci Sbc, TH350, 3200 stall, 3.73 gear Last edited by 383 Stroker; 01-25-2003 at 01:54 AM.

01-25-2003, 01:56 AM	#5
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Some of them will have a plug in on the passenger side. Is that the one you are talking about? If it is, then it is part of the emissions control. It's a temp switch that partly controls the vacuum solenoid. You won't need it so your best bet is to plug it. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

01-25-2003, 02:23 AM	#6
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Bingo ! Thats what it is. Its a temp switch. Its on the passenger side just behind the kick down cable. It looks just like a water temperature sensor with one male 1/4" spade terminal . I had the valve body apart and I know its not a lockup model. Yep. Temp switch. Thanks for the help! __________________ No truck :-(

01-25-2003, 04:04 AM	#7
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Nah thats not it. Its a pressure switch. Its like the oil pressure sensor. You know. The kind like you find on a small block with an electric oil pressure gage or an idiot light. Its got 1/8" NPT threads and a 1" hex head with a single male spade terminal. Now I am confused. Its not a solenoid like youd find with a lockup . What is this thing. It's probably emissions related but what does it do? __________________ No truck :-(

01-25-2003, 12:53 AM	#3
rustedchevy Account Suspended Join Date: Jan 2003 Location: il Posts: 115	you have to remember that soem th350 were C models and others were not

01-25-2003, 01:45 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Mike, are you 100% sure it is a TH350 and not a 400?

01-25-2003, 09:34 AM	#8
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	If it is for the TCS system that came stock on these trucks, it is a high gear indicator. I have never seen one in person, but if it is a pressure switch like you say, then it must detect the pressure in the third gear clutch hydraulic circuit to indicate that the tranny is in third gear. The TCS system also uses a relay (mounted on the vacuum canister on the firewall), a vacuum solenoid in line between the carb and the distributor, and a temperature switch on the engine. Unless all this stuff is hooked up and working, you can ignore the switch on the tranny. __________________ Tim Last edited by Blazer1970; 01-25-2003 at 09:36 AM.

01-25-2003, 12:27 PM	#9
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	I removed that switch and replaced it with the sender for my Autometer transmission temperature gauge. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

01-25-2003, 01:01 PM	#10
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Thats it. Got to be TCS. It came out of a 72 1/2 ton so that makes sense. Might be the good basis for a hi speed ignition retard setup for drag racing....hmmmm. __________________ No truck :-(



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