Lazy Lock-Up??
11-28-2006, 03:43 PM
#1
Lazy Lock-Up?? I am getting frustrated here 
I have less than 1000 miles on my new trans & Converter (Yank SS4000) Here is what it's doing..When the Converter locks up at 45 it sorta "Slips in" instead of a total lock(would snap lock, like a shift)..Feels like a slipping trans when the converter locks. It just started doing this, The Converter does stay locked but it does what I described. Trans shifts good & converter says locked, just a slippy lock up..lol. Anyone heard of this?
I have less than 1000 miles on my new trans & Converter (Yank SS4000) Here is what it's doing..When the Converter locks up at 45 it sorta "Slips in" instead of a total lock(would snap lock, like a shift)..Feels like a slipping trans when the converter locks. It just started doing this, The Converter does stay locked but it does what I described. Trans shifts good & converter says locked, just a slippy lock up..lol. Anyone heard of this? 
11-28-2006, 07:15 PM
#7
My Vig 3400 9.5" is Multidisc 3plate TCC.. it "snaps" into lockup, my TCI 3400 did the same, little more pronounced than stock.. Only time i heard of it doing that was already stated by others, Worn or malfunctioning TCC, or a tuning issue.
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11-28-2006, 07:58 PM
#8
Originally Posted by Yank
Try to reset the PCM as it has a pwm feature
unless you had it removed with tuning or internal trans work also are you running a synthetic fluid as some brands allow for more slip
unless you had it removed with tuning or internal trans work also are you running a synthetic fluid as some brands allow for more slip
11-28-2006, 08:48 PM
#9
Re-setting the PCM did nothing..Here is the whole story...Bought rebuilt Race transmission from reputable shop here in Cali, Guy has built thousands of transmissions, also bought new Yank Converter..I posted on here when I 1st got everything installed that the Converter was locking & unlocking..I had a Vigilante before this with no lock, unlock issues..had a tuner check it out & It seemed we determined that it was in the tune, so he upped the misfire table to max & that cured the problem. NOW about 500 miles later, all of a sudden the converter locks sloppily, I just drove the car & when I am cruising at about 60(Locked) & barely hit the gas it is half locked & unlocked like it's slipping..What do you think? Should I have the tune looked at again? This is not an easy thing for me if I have to yank(no pun intended) that converter out, I have to pay a shop for labor, AGAIN
11-28-2006, 09:00 PM
#10
I am sure one of the resident Trans guys will give some good advice should help.. go to a pro shop if you have one nearby should be able to scan the trans while you're driving and be able to see what's up, I know my (the one I use) shop can do it..
11-29-2006, 08:28 PM
#13
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The TCC has two valves controlling lockup. One is
all-or-nothing. The other is a PWM (pulse width
modulated) pressure control valve. The one is for
applied/not. The other sets available pressure
anywhere from 0% to 100% -of current main line
pressure-. Two issues in that. One, the apply is
"feathered" and slowly ramps up the TCC duty.
This is your soft apply, a smaller clutch like in a
10" converter will not have the same grab as the
larger stocker for same pressure and perssure
comes on slow. Two, commanded line pressure
at light cruise is 0%. That's not zero absolute but
it is bare minimum thought necessary for stock.
Get a harder apply by raising the TCC Duty Min
value. Get more pressure to work with by bumping
up the main line.
There is also a slip-based adaptation in the TCC.
This is nothing but trouble. On a good day it will
back out pressure and then next day you'll be
surprised by slip that shows up, wait for it to learn
back out, day after that you're back to hard applies.
Around and around.
all-or-nothing. The other is a PWM (pulse width
modulated) pressure control valve. The one is for
applied/not. The other sets available pressure
anywhere from 0% to 100% -of current main line
pressure-. Two issues in that. One, the apply is
"feathered" and slowly ramps up the TCC duty.
This is your soft apply, a smaller clutch like in a
10" converter will not have the same grab as the
larger stocker for same pressure and perssure
comes on slow. Two, commanded line pressure
at light cruise is 0%. That's not zero absolute but
it is bare minimum thought necessary for stock.
Get a harder apply by raising the TCC Duty Min
value. Get more pressure to work with by bumping
up the main line.
There is also a slip-based adaptation in the TCC.
This is nothing but trouble. On a good day it will
back out pressure and then next day you'll be
surprised by slip that shows up, wait for it to learn
back out, day after that you're back to hard applies.
Around and around.
11-29-2006, 09:02 PM
#15
One possibility if the pwm wasnt disabled in the build or was disabled by fixing the vavle in place is that either the pwm screen has become clogged , the pwm solinoid itself is failing or in the case of the valve fixed in place whatever method used may have come loose , each of these would account for a sudden change in lockup
__________________
11-30-2006, 03:49 PM
#16
Here is what the builder of the trans told me. I am going by memory cause I lost the Fuggin paper I wrote it on...
1) PWM was disabled, so that's not the problem
2)could be a leaking TCC Selenoid. he said to replace it.
3) If tuner can lock & unlock the converter, It's in the tune
4) If the input shaft seal is chewed up or missing, it's the converter
Car still shifts the same as when I got it, So it's leaning towards the lock-up clutches in the converter are toast with 1000 miles on it...I am not sure though, So I am not blaming anyone yet..Stay tuned. I just hope Yank will step up & replace the Verter, if That's the problem, I PM'd Dave & he didn't respond again to this thread..So Bottom line, I spent $3000 & have to spend another $400 or more on labor & parts to fix the problem. This really sucks.
1) PWM was disabled, so that's not the problem
2)could be a leaking TCC Selenoid. he said to replace it.
3) If tuner can lock & unlock the converter, It's in the tune
4) If the input shaft seal is chewed up or missing, it's the converter
Car still shifts the same as when I got it, So it's leaning towards the lock-up clutches in the converter are toast with 1000 miles on it...I am not sure though, So I am not blaming anyone yet..Stay tuned. I just hope Yank will step up & replace the Verter, if That's the problem, I PM'd Dave & he didn't respond again to this thread..So Bottom line, I spent $3000 & have to spend another $400 or more on labor & parts to fix the problem. This really sucks.
11-30-2006, 04:26 PM
#17
Not necessarily. Another way of checking the converter for proper operation is to drive the vehicle at a constant speed, anything above 60 mph is fine. While holding a constant light throttle pressure, lightly apply and release the brake with your left foot. Watch your tach while doing this, not hard at all to do. You will feel it coming in and out of lock-up. If indeed PWM was disabled then you should be able to feel a very distinct bump when the clutch applies.
What is the condition of the fluid? Is it burnt smelling or discolored? If so then maybe there is a converter issue. How did the builder go about disabling PWM? I would suspect that if the converter clutch were burned it would not hold well at all. I would bet there is a PWM issue causing the symptom, disabled or not. What you described is a very predictable typical learning, adaptive cycle the PCM is designed to perform.
g
What is the condition of the fluid? Is it burnt smelling or discolored? If so then maybe there is a converter issue. How did the builder go about disabling PWM? I would suspect that if the converter clutch were burned it would not hold well at all. I would bet there is a PWM issue causing the symptom, disabled or not. What you described is a very predictable typical learning, adaptive cycle the PCM is designed to perform.
g
11-30-2006, 07:27 PM
#18
Originally Posted by Ratchthed
Not necessarily. Another way of checking the converter for proper operation is to drive the vehicle at a constant speed, anything above 60 mph is fine. While holding a constant light throttle pressure, lightly apply and release the brake with your left foot. Watch your tach while doing this, not hard at all to do. You will feel it coming in and out of lock-up. If indeed PWM was disabled then you should be able to feel a very distinct bump when the clutch applies.
What is the condition of the fluid? Is it burnt smelling or discolored? If so then maybe there is a converter issue. How did the builder go about disabling PWM? I would suspect that if the converter clutch were burned it would not hold well at all. I would bet there is a PWM issue causing the symptom, disabled or not. What you described is a very predictable typical learning, adaptive cycle the PCM is designed to perform.
g
What is the condition of the fluid? Is it burnt smelling or discolored? If so then maybe there is a converter issue. How did the builder go about disabling PWM? I would suspect that if the converter clutch were burned it would not hold well at all. I would bet there is a PWM issue causing the symptom, disabled or not. What you described is a very predictable typical learning, adaptive cycle the PCM is designed to perform.
g
12-01-2006, 09:40 AM
#20
Originally Posted by Dan
I did your test tonight..I can't feel the converter locking & unlocking but I can hear it. There is no distinct bump, just a change in the car sound..(locking, unlocking) Rpm's move up about 300 higher when dis-engaged.
I gotta tell you, it sounds to me that the converter is doing what it is told to do. The only way to determine if the converter clutch is slipping is to take it apart and look at it. I just don't think there is enough evidence here to warrant that.
I would bet that the PWM is the cause of the symptom you described. But the real question is, does the vehicle have a problem... the simple answer is no in my opinion. You are feeling a Pulse width Modulated converter lock-up and that is not a bad thing at all.
g