tc shutter while driving in gear locked
tc shutter while driving in gear locked i was logging around today, trying to pin point the trouble spots.
FO starters, i have tons of kr at idle and when tc is locked...that is a very mind antagonizing subject and i will stay away from that unless anyone can assist....
anyways, im trying to resolve why my car shutters when in 4th gear, tc locked, all the way to 60mph or so. The only way i can describe this shutter is when you shift (manual trans) into a gear that is to low (example, 5th @800rpms instead of 4th @1100rpms....where you should be) it shutters until you get high enough in the rpm range to calm itself.
MAke sense?
Also, when logging, as soon as i lock 4th, its ine, but as i start to reduce tps%, then it starts to shutter....those this all the way up to 60...
so i figure that maybe two things are going on, there is to much difference in timing between low tps and no tps in gear (4th locks around 37mph, around 1200-1300) OR, there isnt enough aiflow at that range to maintain its stability.
Im new still and i have tried looking around and i cant really pin point (except raising the tc lock-up....there has to be a way to fix this!) which parameters to start on.
Any suggestions?
Oh, im on a 408ci with a ls1 intake...you think that may have something to do with it? I know its low of airflow but there has to be a way to compensate wuntil the 90mm setup.
thanks, sorry for the length!!
FO starters, i have tons of kr at idle and when tc is locked...that is a very mind antagonizing subject and i will stay away from that unless anyone can assist....
anyways, im trying to resolve why my car shutters when in 4th gear, tc locked, all the way to 60mph or so. The only way i can describe this shutter is when you shift (manual trans) into a gear that is to low (example, 5th @800rpms instead of 4th @1100rpms....where you should be) it shutters until you get high enough in the rpm range to calm itself.
MAke sense?
Also, when logging, as soon as i lock 4th, its ine, but as i start to reduce tps%, then it starts to shutter....those this all the way up to 60...
so i figure that maybe two things are going on, there is to much difference in timing between low tps and no tps in gear (4th locks around 37mph, around 1200-1300) OR, there isnt enough aiflow at that range to maintain its stability.
Im new still and i have tried looking around and i cant really pin point (except raising the tc lock-up....there has to be a way to fix this!) which parameters to start on.
Any suggestions?
Oh, im on a 408ci with a ls1 intake...you think that may have something to do with it? I know its low of airflow but there has to be a way to compensate wuntil the 90mm setup.
thanks, sorry for the length!!
Easy, the Torque Convertor Clutch is bogging just like a M6 clutch would. You need to tune it and it will stop. Search here or Auto Trans on TCC Tuning. I had to eventually drive, look at mph it effected and adjust the TCC tune accordingly. If you need some help with it after the search, you can email me,
cat3n4@gmail.com
I know its a bitch, but I got the info from someone else, it was never posted on the site, so I am not at liberty to do that. I can share what needs to be done though and its not to hard.
cat3n4@gmail.com
I know its a bitch, but I got the info from someone else, it was never posted on the site, so I am not at liberty to do that. I can share what needs to be done though and its not to hard.
Fast chatter (like, or nearly, a squeal) is probably clutch
friction material, line /TCC PWM pressure. Slow chatter
is probably misfires.
My observation is, there's a range of TCC apply pressures
that will let aftermarket clutches squeal / chatter. Very
light, just slips; very hard, just grabs; some "sweet spot"
in the middle just bounces (like wheel hop for your trans).
Putting the TCC PWM to a hard-switching mode helps.
That means increasing the "offset" value to 98% (or
100% but I never tried that). This will eliminate the soft
apply that GM put in the program to make all the 60-year-
old Buick drivers who buy hot rod Camaros, happy.
But you're still left with a line%-load profile that is too
weak at low pedal to give the TCC any useful juice to
clamp with. There (presently) the only option is to decrease
the force motor current at low load-torque values until the
clutch holds reasonably, and perhaps bring in the unlock
point closer to where slip starts. You don't want to be sanding
the clutch all the time, at some point it's kinder to just let go.
There seems to be some "learning" process that lurks here
too, which will fight you to some extent. If you make the
TCC quit slipping one day, don't be surprised to see it come
back in a couple. It seems to "want" to slip, some. Haven't
found a way to make it stay put.
friction material, line /TCC PWM pressure. Slow chatter
is probably misfires.
My observation is, there's a range of TCC apply pressures
that will let aftermarket clutches squeal / chatter. Very
light, just slips; very hard, just grabs; some "sweet spot"
in the middle just bounces (like wheel hop for your trans).
Putting the TCC PWM to a hard-switching mode helps.
That means increasing the "offset" value to 98% (or
100% but I never tried that). This will eliminate the soft
apply that GM put in the program to make all the 60-year-
old Buick drivers who buy hot rod Camaros, happy.
But you're still left with a line%-load profile that is too
weak at low pedal to give the TCC any useful juice to
clamp with. There (presently) the only option is to decrease
the force motor current at low load-torque values until the
clutch holds reasonably, and perhaps bring in the unlock
point closer to where slip starts. You don't want to be sanding
the clutch all the time, at some point it's kinder to just let go.
There seems to be some "learning" process that lurks here
too, which will fight you to some extent. If you make the
TCC quit slipping one day, don't be surprised to see it come
back in a couple. It seems to "want" to slip, some. Haven't
found a way to make it stay put.
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thanks jimmy, but maybe im not understanding you correctly.
ITs not like she is slipping. THe slip rpm'z are pretty low when locked...its more like the whole drivetrain starts bucking. It almost sounds like teh driveshaft, knowing that it has a little play in it (meaning it isnt mounted flush, it can slide back and forth a bit), is the one making the noie because it when the drivetrain bucks back and forth, it is puching it therefore hiting the joints on both sides.....
i dont know? a little clarification of your previous post would help some....thanks blue!
edit: TTT by the way........
Jimmy, after reading your post again, i think i finally got wat your saying.... will gives a try. any updates on your search for a permanent solution?
i just went through my hp tuner editor files and i cant seem to find the tables or "values" you speak of. Help would be much appreciated...
thanks!!
ITs not like she is slipping. THe slip rpm'z are pretty low when locked...its more like the whole drivetrain starts bucking. It almost sounds like teh driveshaft, knowing that it has a little play in it (meaning it isnt mounted flush, it can slide back and forth a bit), is the one making the noie because it when the drivetrain bucks back and forth, it is puching it therefore hiting the joints on both sides.....
i dont know? a little clarification of your previous post would help some....thanks blue!
edit: TTT by the way........
Jimmy, after reading your post again, i think i finally got wat your saying.... will gives a try. any updates on your search for a permanent solution?
i just went through my hp tuner editor files and i cant seem to find the tables or "values" you speak of. Help would be much appreciated...
thanks!!
Last edited by obZidian; Aug 16, 2005 at 01:00 AM.
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