Torque converter lockup project
Thread Starter
Instructor
Joined: Aug 2006
Posts: 188
Likes: 1
From: Kamloops BC
Torque converter lockup project
I am planning a project where I wire up the TCC circuit on my 81.
I know that by grounding the tan/black wire that was on terminal P of the CCC I can get the converter to lock but I want things a little more automated.
I plan on using the VSS (brown,terminal 16 + ground)and a frequency switch to lockup the tranny. The VSS gives 2000 pulses per mile so at 45 mph that works out to a frequency of 25 cycles/sec. The switch is available as a kit from Austrailia for $40.00.
I also plan on using the 3rd gear switch from the transmission (brown terminal 17), I am not sure but I would guess that this switch is grounded when in 3rd gear. This will work as I will wire the tan/black wire through the frequency switch and then to the 3rd gear switch in series.
If all works out right the lockup will turn on at 45 mph if in 3rd gear and unlock any speed below 40 mph or any gear below 3rd or when the brakes are applied.
All this wiring will be under the accessory box in the back of the car.
The car already had the computer carb and dist changed out on it no way do I want to go back.
any thoughts?
Dale
I know that by grounding the tan/black wire that was on terminal P of the CCC I can get the converter to lock but I want things a little more automated.
I plan on using the VSS (brown,terminal 16 + ground)and a frequency switch to lockup the tranny. The VSS gives 2000 pulses per mile so at 45 mph that works out to a frequency of 25 cycles/sec. The switch is available as a kit from Austrailia for $40.00.
I also plan on using the 3rd gear switch from the transmission (brown terminal 17), I am not sure but I would guess that this switch is grounded when in 3rd gear. This will work as I will wire the tan/black wire through the frequency switch and then to the 3rd gear switch in series.
If all works out right the lockup will turn on at 45 mph if in 3rd gear and unlock any speed below 40 mph or any gear below 3rd or when the brakes are applied.
All this wiring will be under the accessory box in the back of the car.
The car already had the computer carb and dist changed out on it no way do I want to go back.
any thoughts?
Dale
Thread Starter
Instructor
Joined: Aug 2006
Posts: 188
Likes: 1
From: Kamloops BC
yes th350c. I have already tested the transmission to see if it works. I disconnected the tan/black wire from the computer and grounded it while driving at 50 mph. The rpms dropped about 300. I also tested to see if the converter would lock up in 2nd gear and sure enough it does. That is why I plan on using the high gear switch as well.
Thread Starter
Instructor
Joined: Aug 2006
Posts: 188
Likes: 1
From: Kamloops BC
I am not sure how to help you Scott. I guess that you have a TH350C since you asked the question, I didn't know that transmission was used in 1980. How was it connected before? We will need a wiring diagram for your car. With the computer control implimented in the 81 car I would think that the wiring for the converter lockup changed.
Dale
Dale
Thread Starter
Instructor
Joined: Aug 2006
Posts: 188
Likes: 1
From: Kamloops BC
You also need to have lockup "drop" before an automatic downshift. Otherwise you will get a pretty big "shift-shock". The tranny needs to be in converter mode during any shift.
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Team Owner
Joined: Jan 2006
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From: Crossville TN
As long as it's disengaged before the next shift is made, it should be OK. The signal to downshift should trigger the disengage of the lockup clutch [which will be a little before the actual shift]. You may feel a bit of a surge, but it shouldn't do any harm.
