lock-up torque converter
Thread Starter
Instructor
Joined: Apr 2006
Posts: 110
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From: wakefield uk
lock-up torque converter
what are the characteristics of a 1980 lock-up converter,or is it possible to tell if it's working? I understand it all happens at about 30mph,I've identified (with your help )the vacuum switch on the bulkhead,can this be tested?
thanks as always
thanks as always
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
First off nice looking Vette!
When i would drive my 700R4 the difference between lockup and non-lockup was: In non I could blip the throttle going down the road and the tack would jump a few 100 rpm. Lockup is solid just like a real 4 speed manual. No rpm change.
When i would drive my 700R4 the difference between lockup and non-lockup was: In non I could blip the throttle going down the road and the tack would jump a few 100 rpm. Lockup is solid just like a real 4 speed manual. No rpm change.
Race Director
Joined: Jul 2004
Posts: 12,696
Likes: 329
From: Scottsdale Arizona
Originally Posted by gkull
First off nice looking Vette!
When i would drive my 700R4 the difference between lockup and non-lockup was: In non I could blip the throttle going down the road and the tack would jump a few 100 rpm. Lockup is solid just like a real 4 speed manual. No rpm change.
When i would drive my 700R4 the difference between lockup and non-lockup was: In non I could blip the throttle going down the road and the tack would jump a few 100 rpm. Lockup is solid just like a real 4 speed manual. No rpm change.
If your engine is a lower HPP version, you might also notice some bogg down on top gear acceleration. I certainly notice it on my DD.
Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
like the guys said at some point when you have lock up the RPMs will be much more steady and any throttle increase will be seen by a slow rising tcch as opposed to a quick surge in the tach
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
One way to check is to slightly depress the break petal while driving at 55-60 mph and hold constant pressure on the accellerator pedal. You should notice the RPM's increase while the break circuit is activated and then see a decrease in RPM's after your deactivate the break circuit.
Drifting
Joined: Jun 2005
Posts: 1,523
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From: grand prairie texas
Originally Posted by marshrat99
One way to check is to slightly depress the break petal while driving at 55-60 mph and hold constant pressure on the accellerator pedal. You should notice the RPM's increase while the break circuit is activated and then see a decrease in RPM's after your deactivate the break circuit.
Thread Starter
Instructor
Joined: Apr 2006
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From: wakefield uk
Originally Posted by bobs77vet
like the guys said at some point when you have lock up the RPMs will be much more steady and any throttle increase will be seen by a slow rising tcch as opposed to a quick surge in the tach
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Originally Posted by turbovette80
My tach surges between acceleration and overrun about 200 to 300 rpm ,so that means it's not working,is there anything I can do to repair it?
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Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
You can apply 12 volts to the lockup selinoid and you can hear it pic and un pick from under the car. Usually it the clutch it's self that gets burnt out and then it's replacement torq converter time.
Melting Slicks
Joined: Oct 1999
Posts: 2,581
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From: Tolar Texas
Maybe this diagram will help you with troubleshooting.
I wouldn't sweat it too much if you can't get it to work. I ran my TH350C for years without lockup. I doubt that it would significantly improve your fuel economy.
I wouldn't sweat it too much if you can't get it to work. I ran my TH350C for years without lockup. I doubt that it would significantly improve your fuel economy.
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Doesn't sound right.
I believe that vacuum check valve belongs to the vacuum supply for the head lights. It is located near the TCC vacuum switch. Perhaps someone got mixed up once upon a time and stuck the wrong hose to the wrong component.
I believe that vacuum check valve belongs to the vacuum supply for the head lights. It is located near the TCC vacuum switch. Perhaps someone got mixed up once upon a time and stuck the wrong hose to the wrong component.
Safety Car
Joined: Oct 2004
Posts: 3,725
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From: Minnesota
That vacuum switch can be fickle. I installed one with my 700r4. When you say the tach surges do you mean the tach is malfunctioning or is the engine surging? I ask this because my engine would surge from the lockup going in and out under any kind of load. The solution was to install one of those black and white inline check valves on the hose going to the switch. Any junkyard should have these. Now the lockup works as it should. It's like having an intermediate gear between 3rd and OD. I would recommend using the lockup since your gas mileage will be a little better and your tranny will run around 30 degrees cooler.
Thread Starter
Instructor
Joined: Apr 2006
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From: wakefield uk
Well I took the stud blocking the vacuum pipe out,reversed the valve and now everything works purrrrrrfect! locks up at about 30mph disengages with brakes ,45mph comes up at 1500rpm and it pulls like a train! thanks for the help everyone
thanks for the help everyone
