TH350C Lockup Switch Info. Needed
Thread Starter
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
TH350C Lockup Switch Info. Needed
Hi I'm in the process of decomputerizing my 81 C3. It has a TH350C and I've heard of a switch set-up and would like info on the setup.
If anyone has info and possibly pictures of this kind of setup it would be greatly appreciated.I have a B&M lockup controller kit (not installed yet) has anyone used one? What setup would be better? Thanks!
If anyone has info and possibly pictures of this kind of setup it would be greatly appreciated.I have a B&M lockup controller kit (not installed yet) has anyone used one? What setup would be better? Thanks!
Melting Slicks
Joined: May 2003
Posts: 2,078
Likes: 283
From: Dyersburg TN
350c
The TH350c TCC draws 12v from the fuse box through a switch on the brake pedal (to release if you step on brake). The ground is privided via a relay controled by the computer. The ground is the only interaction the computer has with the TCC. The relay should be on the driver's side firewall by the MAP sensor. You will need a alt way to ground, either a manual switch, kit from some company or many use a older no-computerised Corvette vacume switch.
Thread Starter
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
The TH350c TCC draws 12v from the fuse box through a switch on the brake pedal (to release if you step on brake). The ground is privided via a relay controled by the computer. The ground is the only interaction the computer has with the TCC. The relay should be on the driver's side firewall by the MAP sensor. You will need a alt way to ground, either a manual switch, kit from some company or many use a older no-computerised Corvette vacume switch.
Melting Slicks
Joined: May 2003
Posts: 2,078
Likes: 283
From: Dyersburg TN
a 1980 Corvette would have used the vacume switch to control the trans
found this on another site: http://67-72chevytrucks.com/vboard/s...d.php?t=335802
found this on another site: http://67-72chevytrucks.com/vboard/s...d.php?t=335802
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Are you "de-computerizing" for engine controls? Or did the computer or other hardware go bad on you? If you just want the 'stuff' off the engine, keep the computer hooked up to the tranny and pull the connections for the O2 sensor and the distributor & carb connections. That way you can do what you want with the engine, but the tranny will still function via the computer. As long as the safety release switches and the coolant temp sensor are still in the circuit, I believe that it should work normally.
Melting Slicks
Joined: May 2003
Posts: 2,078
Likes: 283
From: Dyersburg TN
to be clear
just to be clear the transmission has 12v from the fuse box when car is running and grounds through the computer. This circuit has a relay in it controlled by the brake light switch. When you step on the brakes, the relay cuts the ground to the transmission turning off the converter lock.
The computer uses the vehicle speed sensor to determine when to provide ground to the transmission. In addition there is a pressure switch in the transmission itself to ensure the TCC only works in 3rd gear.
The short of this is that the transmission just needs a hot and ground to engage the lockup in high gear. To avoid a stall you need the brake system to disengage the lock when brakes are applied. Finally you need a computer, vacuum switch or plain old manual switch to provide the ground.
I think the aftermarket kits do provide their own speed sensors to control when the converter locks. This would probably be useful in fine tuning when you want it to come on.
The computer uses the vehicle speed sensor to determine when to provide ground to the transmission. In addition there is a pressure switch in the transmission itself to ensure the TCC only works in 3rd gear.
The short of this is that the transmission just needs a hot and ground to engage the lockup in high gear. To avoid a stall you need the brake system to disengage the lock when brakes are applied. Finally you need a computer, vacuum switch or plain old manual switch to provide the ground.
I think the aftermarket kits do provide their own speed sensors to control when the converter locks. This would probably be useful in fine tuning when you want it to come on.
Last edited by dburgjohn; Nov 23, 2009 at 11:30 PM. Reason: add picture
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Thread Starter
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
just to be clear the transmission has 12v from the fuse box when car is running and grounds through the computer. This circuit has a relay in it controlled by the brake light switch. When you step on the brakes, the relay cuts the ground to the transmission turning off the converter lock.
The computer uses the vehicle speed sensor to determine when to provide ground to the transmission. In addition there is a pressure switch in the transmission itself to ensure the TCC only works in 3rd gear.
The short of this is that the transmission just needs a hot and ground to engage the lockup in high gear. To avoid a stall you need the brake system to disengage the lock when brakes are applied. Finally you need a computer, vacuum switch or plain old manual switch to provide the ground.
I think the aftermarket kits do provide their own speed sensors to control when the converter locks. This would probably be useful in fine tuning when you want it to come on.
The computer uses the vehicle speed sensor to determine when to provide ground to the transmission. In addition there is a pressure switch in the transmission itself to ensure the TCC only works in 3rd gear.
The short of this is that the transmission just needs a hot and ground to engage the lockup in high gear. To avoid a stall you need the brake system to disengage the lock when brakes are applied. Finally you need a computer, vacuum switch or plain old manual switch to provide the ground.
I think the aftermarket kits do provide their own speed sensors to control when the converter locks. This would probably be useful in fine tuning when you want it to come on.
