Torque converter is acting strange...

[White93z34]

alright this is a problem i've been having for a little while now, and it can be downright annoying, when i'm driving down the highway maintaining a consistant speed. on occasion the TQ will unlock, then lock, and keep on doing that untill i press the brake pedel since that forces the TQ to unlock, then it may or may not doit again on that trip. also letting off the gas and coasting for awhile will make it go away as well. from what i understand my tranny was rebuilt somewhere in the vacinity of 50k ago.

[Crazy K]

hmm. not sure, but I suggest popping the brake light switch off, opening it up and cleaning the contacts to see it it may make a difference, and I like to dab a bit of grease on it to keep corrosion out, and snapping it in place. (assuming plunger type with 3 possible contact switches.)

[1990lumina]

How cold it is around you these days, and what wamr is your engine getting??

 

I find with my car when it is not warm the TC will unlock and rev the engine higher to warm it up...then lock. However my engine will cool down again travelling down the highway so it will again unlock and warm the engine. This *may* be your problem, I'm not sure??

[Supreme Cutlass]

hmm. not sure, but I suggest popping the brake light switch off, opening it up and cleaning the contacts to see it it may make a difference, and I like to dab a bit of grease on it to keep corrosion out, and snapping it in place. (assuming plunger type with 3 possible contact switches.)

So, how does the brake light switch create his torque converter problem?

 

Could it possibly the TCC solenoid failing?

Maybe one of the peramiters that triggers the TCC is fluctuating:

 

Coolant temperature sensor (doubtfull)

Correct transmission fluid pressure

the ECM uses 2,3,4 gear switches to tell when to engage the clutch, maybe a problem with one of them

TPS issue?

[Crazy K]

interesting idea! I think that the sensor that tells the trans to lock/unlock was actually in the transmission, however. Do you have auxilary transmission coolers installed? I've read that they should be installed inline before the factory radiator trans cooler to preven over-cooling of the trans.

 

1990lumina, are you running a regular 195 thermo?

if not, and since they are so easy to swap on the 3.1 you might put one in for the winter and see if it makes a difference in the trannys tcc operation, and to give you better heat.

[1990lumina]

Guess I didn't read that part clearly. I read "locks and unlock at constant speed". I know the brakes will unlock it....but if it locks again after he goes back up to speed then it is functioning fine. The TC shouldn't stay locked if you hit the brakes.

 

I know on my car if you play around with the brake and accellerator when it is doing this you can stop it from doing it...I just get pissed off, drop the hammer and let it rip. That warms it up some, then it doesn't happen again

[Crazy K]

So, how does the brake light switch create his torque converter problem?

TPS issue?

The brake light switch is a three part switch, one portion of it disengages the TCC. It is a closed circuit except when the brakes are applied. An intermittant contact could be at fault,

But I think the second idea is more likely, as the fault of an overcooling tranny/engine/powertrain.

 

(my 95 CS TCC doesn't work, I've discovered, and I need to chase these same gremilins)

[White93z34]

well since my car is a LQ1 car i do have the factory aux trans cooler. last year about this time i changed the ATF and filter, it was quite clean even then with at least 40k on it or so. and i honestly coulden't tell you if it did it before i changed the fluid and filter.

 

the TPS, i really don't see how this could cause it, but its something thats cake enough to change.

 

i realllly hope its not a failing TCC.

[Grand Moff Joseph]

My 3.1 car does this too on the highway. I'll be crusing down the road, then the car will literally lunge a couple of times, as the TCC kicks out, then in, then out again. All I have to do to stop it is push the gas down, or let off of it completely.

 

IIRC, the TCC is supposed to lock between 55-59, so IMO, the damn thing is getting confused, and keeps going back and forth.

 

Gotta love the 440T4... :?

[digitaloutsider]

well since my car is a LQ1 car i do have the factory aux trans cooler

This isn't really LQ1-specific. my 3.1 had the same thing.

[White93z34]

well since my car is a LQ1 car i do have the factory aux trans cooler

This isn't really LQ1-specific. my 3.1 had the same thing.

 

regaurdless any A4 car that got the LQ1 got a aux. cooler, but thats not really the point of this topic.

 

so far i've found that in my 40 minute drive to work this morning it did it only once i steped on the brake, it stoped doing it and i continued my drive to work normally. also it dosen't much matter the speed that i'm traveling at, for example i was pushing 75 or so on the highway today and it still did it.

 

all i know is i'm gona be real mad if i rip the side pan off the trans to replace the TCC and it still does it afterwards, that is where it is correct?

[Supreme Cutlass]

 

all i know is i'm gona be real mad if i rip the side pan off the trans to replace the TCC and it still does it afterwards, that is where it is correct?

 

 

Just unplug the connector on the front of the tranny, and there ya go. I unplugged mine, the loss in mileage isn't THAT bad.

[White93z34]

see i'd do that, except i like to do things properly. and with gas at 2.19 a gallon i don't want to loose anything.

 

also if i unpluged the connector on the transmission, it would not know WTF to do since i have the 4t60E wheras you got a 4t60

[White93z34]

well today in my travles i was at a transmission shop and got to ask the one guy there about my TQ problem he also mentioned possably having a bad TPS, so in the next few days here i'm gona change that out and see if it nets me anything.

[Supreme Cutlass]

Depending on the store, autozone might be able to test it

[corning_d3]

I've had my TCC act up a few times. The first was a bad TPS (Quick throttle movements disengage TCC). The second time was a mis-adjusted brake light switch. The sensors responsible for torque converter lock-up aren't inside the transmission, except for two(VSS, which is on the pass. side, over the differential and Fluid Temp. Sensor, under valve body). It uses the MAP, TPS, ECT and RPM signal. The actual signal to lock up the converter comes from the PCM, which bases its decision on all inputs from these sensors. I would suggest 2 things: either cover the radiator partially with cardboard and see if the TCC acts normal, or (My choice) have the codes checked with a GM Tech II scan tool. This scan tool can see codes that do not set a MIL. You may have a sensor that's jumping out of limits, but acted normal when the PCM was testing it. I've removed the catalytic converter on my car, and it took up to 500 miles for the O2 catalyst monitor to set a "hard" code. For reference, if you unplug the connector on a 4T60E, it will die when you drop it into drive, probably because the TCC solenoid needs power to disengage the TCC.

[Supreme Cutlass]

I've had my TCC act up a few times. The first was a bad TPS (Quick throttle movements disengage TCC). The second time was a mis-adjusted brake light switch. The sensors responsible for torque converter lock-up aren't inside the transmission, except for two(VSS, which is on the pass. side, over the differential and Fluid Temp. Sensor, under valve body). It uses the MAP, TPS, ECT and RPM signal. The actual signal to lock up the converter comes from the PCM, which bases its decision on all inputs from these sensors. I would suggest 2 things: either cover the radiator partially with cardboard and see if the TCC acts normal, or (My choice) have the codes checked with a GM Tech II scan tool. This scan tool can see codes that do not set a MIL. You may have a sensor that's jumping out of limits, but acted normal when the PCM was testing it. I've removed the catalytic converter on my car, and it took up to 500 miles for the O2 catalyst monitor to set a "hard" code. For reference, if you unplug the connector on a 4T60E, it will die when you drop it into drive, probably because the TCC solenoid needs power to disengage the TCC.

 

First off, a Tech II scanner will not work, as his is OBD I

 

Second, there ARE sensors inside the transmission that detect what gear it is currently in that the ECM takes into account (I have a diagram if you wish to see it) Edit- as on a 92 4t60-E

 

Lastly, it won't DIE if you unplug the connector, unless your clutch is stuck in.

[Crazy K]

technically... the tranmission in the event of a failure would lock into third gear. If the plug were unplugged for instance.

[corning_d3]

Yeah, a Tech II will work, I use one every day(Mon.-Fri). You just have to have the OBD I connector and cig. lighter adapter. Unplug a 4T60E and see......Also, limp in mode is second gear, because both solenoids are off in second....

[Crazy K]

Also, limp in mode is second gear, because both solenoids are off in second....

No they're not!

 

ok ok, the reference manual I have is for a 94 CS 3.1. In second the A solenoid is off but B is ON. In third they are both off. I would assume they didn't redesign this, but they might have. What's your info from?

[corning_d3]

A Mitchell professional service edition domestic transmission repair manual. I think i found our disagreement. It will operate in 3rd when in the OD position, but when pulled into manual D or second, it will operate in 2nd(manual override over electric). I found this on 60degreeV6, too......

 

http://60degreev6.com/images/4T60E/4t60E_elec.jpg

[Crazy K]

TOUCHE you're on the money!

I understand failsafe mode would be third in overdrive(what everyone puts their gearshifts in anyhow). The service manual does indicate the plug being loose would lock car in third gear with second being manually possible, but with no explaination. reading on, when the tranny in manual second it actually hydraulicly bypasses the B solenoid. In D or OD, the B Solenoid would be on. The tranny also shifts into 1st electrically, so manualing trying probably means it would stay in second. -Ken

what do ya think?

[corning_d3]

Sounds right on to me. Who'da thought of an electronic transmission with 2-3 and 3-4 manual override valves??? Speaking of transmissions, have you heard about the new 6 speed automatic FWD transmission co-developed by Chevy and Ford? Should be interesting.. (please let there be plenty of engine/trans. combo's, cuz i smell a 6 speed 3.1/3.4/3.8 Monte!!)

[Crazy K]

I'm not sure that I'w want to touch that 6 speed if ford touched it! How about instead getting a viper 6 speed tranny and converting your car to RWD?

 

The manual over ride values are dual purpose, When everything works properly they nullify the solenoids when manually downshifted, and in the event of an elctric failure still allow you to manually select third or second gear and allow you to at least move. There won't be any automatic shifting however, with a tranny in that condition.

 

On a side note.... I could always throw a 4t60e into my vert. I already can't make it go unless i drive it in second and then fling it into OD while traveling at 50mph... (3rd is dead) at least it would be an improvement (btw has anyone tried linking a 4t60-e to a 3.1???)

edit: vert is a 91 with a 4t60, and 3.1 motor

[corning_d3]

I believe most 3.1 engines are coupled to a 4t60-e. My '96 Monte has a 3.1 w/ a 4t60-e. Unless your refering to a 4t440 or a 4t60 to 4t60-e conversion..i think that could be done with a newer PCM. AS far as the 6-speed, we'll soon see how it goes on the '06 Saturns....