[1985/A4] Torque Converter Lockup Questions ...
12-08-2006, 04:01 PM
#1
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St. Jude Donor '06
[1985/A4] Torque Converter Lockup Questions ...
Some questions about a stock 1985/A4 torque converter and lock-up (please remember that I'm a transmission idiot and have mercy):
1) When should the torque converter lock-up? Is it at a (reasonably) precise speed or are there other influencing factors?
2) How would one change the lock-up speed (again for a stock torque converter) ?
3) Do the same things that cause lock-up cause "un-lock-up"?
4) If it turns out that it's not locking-up at the correct speed, what is about to die on me? Notice that I've learned something - I'm not asking if something is about to die on me ...
1) When should the torque converter lock-up? Is it at a (reasonably) precise speed or are there other influencing factors?
2) How would one change the lock-up speed (again for a stock torque converter) ?
3) Do the same things that cause lock-up cause "un-lock-up"?
4) If it turns out that it's not locking-up at the correct speed, what is about to die on me? Notice that I've learned something - I'm not asking if something is about to die on me ...
12-08-2006, 04:47 PM
#2
Originally Posted by j3studio
Some questions about a stock 1985/A4 torque converter and lock-up (please remember that I'm a transmission idiot and have mercy):
1) When should the torque converter lock-up? Is it at a (reasonably) precise speed or are there other influencing factors?
2) How would one change the lock-up speed (again for a stock torque converter) ?
3) Do the same things that cause lock-up cause "un-lock-up"?
4) If it turns out that it's not locking-up at the correct speed, what is about to die on me? Notice that I've learned something - I'm not asking if something is about to die on me ...
1) When should the torque converter lock-up? Is it at a (reasonably) precise speed or are there other influencing factors?
2) How would one change the lock-up speed (again for a stock torque converter) ?
3) Do the same things that cause lock-up cause "un-lock-up"?
4) If it turns out that it's not locking-up at the correct speed, what is about to die on me? Notice that I've learned something - I'm not asking if something is about to die on me ...
Lock up happens when the pressure switches in the trans and the ecm meet the conditions. Solenoid then moves the valve, allowing the lock up plate in the trans to push tight against the rear of the converter.
Brake switch will deactivate lock up.
Ecm can disengage lock up.
Lock up speed can be changed by reprogramming. The lock up can also be manipulated to work in 2nd, third or 4th only by rewiring the pressure switches.
I have never seen the lock up speed change when something is defective in the trans. Ecm, speedo sensor, cts problem etc, could affect it though.
12-08-2006, 04:59 PM
#3
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Originally Posted by Pete K
The prom has lock and unlock speeds (in mph) programmed into it.
Lock up happens when the pressure switches in the trans and the ecm meet the conditions. Solenoid then moves the valve, allowing the lock up plate in the trans to push tight against the rear of the converter.
Brake switch will deactivate lock up.
Ecm can disengage lock up.
Lock up speed can be changed by reprogramming. The lock up can also be manipulated to work in 2nd, third or 4th only by rewiring the pressure switches.
I have never seen the lock up speed change when something is defective in the trans. Ecm, speedo sensor, cts problem etc, could affect it though.
Lock up happens when the pressure switches in the trans and the ecm meet the conditions. Solenoid then moves the valve, allowing the lock up plate in the trans to push tight against the rear of the converter.
Brake switch will deactivate lock up.
Ecm can disengage lock up.
Lock up speed can be changed by reprogramming. The lock up can also be manipulated to work in 2nd, third or 4th only by rewiring the pressure switches.
I have never seen the lock up speed change when something is defective in the trans. Ecm, speedo sensor, cts problem etc, could affect it though.
Are there specs for the factory settings for lock-up? Are they the same for lock and un-lock?
Will even a slight brake application take the transmission out of lock-up? I think I remembering hearing this ...
What does CTS stand for?
Last edited by j3studio; 12-08-2006 at 05:10 PM.
12-08-2006, 05:09 PM
#4
Originally Posted by j3studio
Just the guy I was hoping would answer!
Are the specs for the factory settings for lock-up? Are they the same for lock and un-lock?
Will even a slight brake application take the transmission out of lock-up? I think I remembering hearing this ...
What does CTS stand for?
Are the specs for the factory settings for lock-up? Are they the same for lock and un-lock?
Will even a slight brake application take the transmission out of lock-up? I think I remembering hearing this ...
What does CTS stand for?
I "think" there are 2 mph tables for lock up speeds. Not sure though. I only worry about the warm lock up speeds.
If the brakes apply enough to light the brake light, the car should jump out of lock up.
If I recall, the unlock speed is about 5 mph lower than the lock up speed. GM did everything they could do to get the 700r4 to shift into lock up and high gear quickly to get the best fuel milage. Leaving the torque converter locked as long as possible(by making the unlock mph lower) was normal. Governor and lock up mods are often appreciated and requested by people I do work for. Makes driving in traffic a bit more pleasant.
12-08-2006, 05:12 PM
#5
12-08-2006, 05:13 PM
#6
Le Mans Master
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Originally Posted by Pete K
CTS is coolant temp sensor.
I "think" there are 2 mph tables for lock up speeds. Not sure though. I only worry about the warm lock up speeds.
If the brakes apply enough to light the brake light, the car should jump out of lock up.
If I recall, the unlock speed is about 5 mph lower than the lock up speed. GM did everything they could do to get the 700r4 to shift into lock up and high gear quickly to get the best fuel milage. Leaving the torque converter locked as long as possible(by making the unlock mph lower) was normal. Governor and lock up mods are often appreciated and requested by people I do work for. Makes driving in traffic a bit more pleasant.
I "think" there are 2 mph tables for lock up speeds. Not sure though. I only worry about the warm lock up speeds.
If the brakes apply enough to light the brake light, the car should jump out of lock up.
If I recall, the unlock speed is about 5 mph lower than the lock up speed. GM did everything they could do to get the 700r4 to shift into lock up and high gear quickly to get the best fuel milage. Leaving the torque converter locked as long as possible(by making the unlock mph lower) was normal. Governor and lock up mods are often appreciated and requested by people I do work for. Makes driving in traffic a bit more pleasant.
12-08-2006, 05:41 PM
#7
If you have a specific problem you are trying to fix, I can pm my cell phone number. I have free weekends and long distance and often help out forum members when I can. I have 1/2 dozen calls to return this saturday, and have no problem helping if you need it.
12-08-2006, 06:57 PM
#8
Race Director
FWIW, my 93 locks up at 49 mph...i actually had a problem at the drag strip earlier this year with the lock up...I made a pass and was on my way to a PB...at about 1000' the converter locked up and the car nose dived...then it picked up again ..I got a PB but it could have been much better...
It turns out my computer was calling for the converter to lock up at 90 MPH even at WOT...nuts I tell ya!....I had a new chip burned and moved that MPH up to 115 and have not had a problem since...I always thought the converter would never lock up at WOT...boy, was I wrong...this must have had to do with the bigger stall converter I had just put in...went to a 3200 stall Vigilante...
I don't know why this would affect the lock up but it did since it never happened before...I'm sure the tranny cooler I put in with the 3200 converter had nothing to do with it...it's always something, isn't it?...lol
It turns out my computer was calling for the converter to lock up at 90 MPH even at WOT...nuts I tell ya!....I had a new chip burned and moved that MPH up to 115 and have not had a problem since...I always thought the converter would never lock up at WOT...boy, was I wrong...this must have had to do with the bigger stall converter I had just put in...went to a 3200 stall Vigilante...
I don't know why this would affect the lock up but it did since it never happened before...I'm sure the tranny cooler I put in with the 3200 converter had nothing to do with it...it's always something, isn't it?...lol
