Auto Trans solenoids
01-09-2006, 12:59 PM
#1
Auto Trans solenoids
I recently had to re-rebuild my auto trans since the shop missed something last Feb. when they originally did it. It was all covered under warranty. Anyways.......I got it back and the torque converter lock up isn't functioning. I took it back and they had it for like a week and told me it's not the transmission itself, it's something outside of it. So of course I will have to pay for anything further. BUT....before the car went in to the shop for the re-rebuild, it was working perfect. My question is.....on one of the forum members CarDomain page(can't remember his name but his cardomain page is like a Factory Service Manual itself) it had trans diagrams. For the trans it shows the Torque Converter Clutch solenoid circuit should have >1v at no lock-up and 8-15v under lockup. Does this mean the circuit can have anywhere in between those numbers or does it go up to 15v ALWAYS? I drove the car and tested voltage at the solenoid connector under the hood and it went up to 10.91volts at 45mph. If so this means my computer is giving the proper voltage and the problem is inside the trans right?
01-09-2006, 02:19 PM
#2
01-09-2006, 03:01 PM
#4
Originally Posted by 91WBSE
I recently had to re-rebuild my auto trans since the shop missed something last Feb. when they originally did it. It was all covered under warranty. Anyways.......I got it back and the torque converter lock up isn't functioning. I took it back and they had it for like a week and told me it's not the transmission itself, it's something outside of it. So of course I will have to pay for anything further. BUT....before the car went in to the shop for the re-rebuild, it was working perfect. My question is.....on one of the forum members CarDomain page(can't remember his name but his cardomain page is like a Factory Service Manual itself) it had trans diagrams. For the trans it shows the Torque Converter Clutch solenoid circuit should have >1v at no lock-up and 8-15v under lockup. Does this mean the circuit can have anywhere in between those numbers or does it go up to 15v ALWAYS? I drove the car and tested voltage at the solenoid connector under the hood and it went up to 10.91volts at 45mph. If so this means my computer is giving the proper voltage and the problem is inside the trans right?
I've noticed on my max (ve) that in colder weather 4th gear takes a hell of a lot longer to engage. At least I hope its 4th gear and not the tq converter. Its easy to notice because the rpm normally is like 2000 at about 70mph, but when it doesnt engage its easily 2300rpm. The difference between 3rd and 4th ratio wise is very little, but its still bad for economy when it doesn't engage. It can take up to 10 min of highway driving to pull 4th. In the winter I install a piece of plastic infront of my external tranny cooler, to prevent over-cooling, but thats still not enough to fix the problem.
01-09-2006, 03:05 PM
#5
Originally Posted by 91WBSE
Ya that's where I got the information. But I'm wondering if the voltage can be anywhere in between those specified on those diagrams or should it go from 8v-15v?
Sorry,i misread your post...I thought you were asking for the site...
:
01-10-2006, 11:06 AM
#6
Originally Posted by eric93SE
well if you have close to 11V and you need between 8 and 15, then the converter should lock up. I would guess that the voltage reading is speed dependent. You could have a faulty solenoid pack.
01-10-2006, 11:42 AM
#7
Originally Posted by 91WBSE
The shop replaced the solenoids AGAIN and it still doesn't lock up. I notice the rpms do drop but its not totally locked up. I can still vary the rpms with slight increase in gas pedal. They're trying to tell me it could be my computer, some sensor, wiring, and anything they do further I will be charged since it was not part of original rebuild. Before I brought it in this past Nov. when the trans blew again the lock-up was working perfect. They did not replace the torque converter this time. I don't know what to do. The way I see it is.....voltage is within the correct parameter so it has to be inside the transmission. Before I picked it up this last time they put 12volts directly to that circuit from battery using switch and with the car in Drive held by the parking brake he flipped the switch and it locked up causing engine to shut off since car was stopped. This was the only way he tested it. I'm thinking it could be different in 4th gear.
You might wanna try a tranny ecu from the junky, you have to make sure its a compatable unit.
I hope your mechanic didn't mess anything up manually engaging the tranny like that.
01-11-2006, 05:46 PM
#8
Senior Member
Join Date: Jul 2005
Location: Townsville, Australia
Posts: 162
Sounds similar to a problem I had/have. the fault in mine also occured after a rebuild, the shop has replaced the solenoid pack twice and the lockup solenoid (it is separate to the rest of them) 3 times, they have fully rebulit the transmission a second time, replaced the converter 3 times, each time from a different supplier and replaced all internal electronic sensors (temp, revolution). They also sent the car to a auto tech. who said he couldn't find any electronic problems. They did all this under warranty.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
01-11-2006, 06:02 PM
#9
Originally Posted by sonicii
Sounds similar to a problem I had/have. the fault in mine also occured after a rebuild, the shop has replaced the solenoid pack twice and the lockup solenoid (it is separate to the rest of them) 3 times, they have fully rebulit the transmission a second time, replaced the converter 3 times, each time from a different supplier and replaced all internal electronic sensors (temp, revolution). They also sent the car to a auto tech. who said he couldn't find any electronic problems. They did all this under warranty.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
01-11-2006, 06:21 PM
#11
Senior Member
Join Date: Jul 2005
Location: Townsville, Australia
Posts: 162
Originally Posted by internetautomar
try adjusting the TPS, sime cars use that to control shifting
If I adjusted the TPS far enough, I could get the transmission to unlock the converter before I could accelerate hard enought for the fault to occur, but each gear would rev out to about 3.5k-4k rpm before shifting, even under light acceleration.
I even tried replacing the TPS in case it had a bad spot giving erratic readings to the ECU and TCU, still no change.
01-12-2006, 08:52 AM
#12
Originally Posted by sonicii
Sounds similar to a problem I had/have. the fault in mine also occured after a rebuild, the shop has replaced the solenoid pack twice and the lockup solenoid (it is separate to the rest of them) 3 times, they have fully rebulit the transmission a second time, replaced the converter 3 times, each time from a different supplier and replaced all internal electronic sensors (temp, revolution). They also sent the car to a auto tech. who said he couldn't find any electronic problems. They did all this under warranty.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
The problem only occurs in my car after the transmission has fully warmed up, then after the converter locks up, if I apply moderate throttle (not sufficient for the TCU to unlock it), the RPM jumps up for a few seconds, then drops back down and then back up again and so on. I have looked at the lockup solenoid connector on the TCU when this occurs and it appears to be trying to unlock and re-lock the converter, as if in response to a detected problem, once I back off the throttle, it stays locked ok.
My diagnosis is that the converter lockup clutch is slipping under load and the TCU is detecting this and unlocking and relocking the converter to try to correct the fault. The shop believed the TCU response is caused by a electronic fault (even though it doesn't happen until the trans is hot)
After being without my car for a total of approx 3 months, and the shop telling me that it is not a mechanical fault, and the auto tech telling me it is not an electronic fault, I decided to try for myself.
I flushed the transmission with fluid designed for a different transmission manufacturer who was having slipping problems with standard dexron fluid, this reduced the problem, and i needed to apply more throttle to cause the fault. Then, since I live in a warm climate, I installed the largest transmission cooler I could find (since the problem only occured with the trans was hot), the problem now does not occur. unless I putter around in city traffic for half an hour then accelerate straight up to 80km/h, and even then it only occurs for a minute or so until the transmission cools down a little.
Sorry I can't offer an absolute solution, but perhaps some information here might help.
01-12-2006, 03:52 PM
#13
Senior Member
Join Date: Jul 2005
Location: Townsville, Australia
Posts: 162
Originally Posted by 91WBSE
Thanks for the info. I too think the torque converter clutch is slipping. I do see it go into lock-up on the tach but it's not totally locked up and I can still vary the rpms a little. I still have ~3k miles left on the warranty. Should I take it back to him again with the diagrams showing what voltage should be and show him that the trans computer is indeed giving proper voltage to the trans and problem lies within transmission? I mean if there's 8-15v at the solenoid connector at lock-up, it's definately inside the trans correct?
01-13-2006, 11:58 AM
#14
Originally Posted by sonicii
The signal from the TCU for the converter lockup is not just a normal voltage that is either 'there or not', it is a pulse width modulated signal, which has a duty cycle of about 5% when unlocked, and about 95% when locked. If you are measuring with a digital multimeter, depending on the meter it is possible to get a reading of 11V even if the duty cycle is not at the full 95% To see if the TCU is trying to lock the converter fully, you really need an oscilloscope. If you feel technically compentent, you could disconnect the lockup pin from the TCU and connect it to battery power via a switch, then when you are up to a suitable speed, you can engage the converter lockup manually and see if you still get a RPM variation, don't give it too much throttle as the lockup clutch isn't designed to cope with too much torque. (the transmission has mechanical lockouts that prevent the converter lockup clutch from engaging when it is in 1st gear.)
Ok the transmission shop tech. had a switch hooked up under the hood and all he did was start the car, put it in drive withe E-brake holding it, flipped the switch and the engine shut off supposedly cause the wheels are stopped and torque converter locked up. If you said that it has mechanical lockouts that prevent it from locking up in first gear, how would he have done this? If the car is sitting still in Drive, the transmission would be in 1st gear.
01-14-2006, 07:50 AM
#15
Originally Posted by 91WBSE
Ok the transmission shop tech. had a switch hooked up under the hood and all he did was start the car, put it in drive withe E-brake holding it, flipped the switch and the engine shut off supposedly cause the wheels are stopped and torque converter locked up. If you said that it has mechanical lockouts that prevent it from locking up in first gear, how would he have done this? If the car is sitting still in Drive, the transmission would be in 1st gear.
I wonder if that test is sufficient. When crusing at 60-70mph the load is probably greater, any chance of slippage will be greater.
I'm not aware of how the TQ lock-up action works (haven't had a look at the book yet) to understand what would be slipping.
01-14-2006, 05:25 PM
#16
Originally Posted by 91WBSE
Ok the transmission shop tech. had a switch hooked up under the hood and all he did was start the car, put it in drive withe E-brake holding it, flipped the switch and the engine shut off supposedly cause the wheels are stopped and torque converter locked up. If you said that it has mechanical lockouts that prevent it from locking up in first gear, how would he have done this? If the car is sitting still in Drive, the transmission would be in 1st gear.
it's a clutch inside the converter.
Normally a converter is just a fluid coupling and has some built in slip which allows the car to idle in gear. But when the converter is in lockup mode it becomes a more direct coupling like a stick shift, you can't idle in gear.
Did that make sense?
01-14-2006, 06:09 PM
#17
Originally Posted by internetautomar
that's how a lockup converter works.
it's a clutch inside the converter.
Normally a converter is just a fluid coupling and has some built in slip which allows the car to idle in gear. But when the converter is in lockup mode it becomes a more direct coupling like a stick shift, you can't idle in gear.
Did that make sense?
it's a clutch inside the converter.
Normally a converter is just a fluid coupling and has some built in slip which allows the car to idle in gear. But when the converter is in lockup mode it becomes a more direct coupling like a stick shift, you can't idle in gear.
Did that make sense?
01-14-2006, 08:51 PM
#18
Originally Posted by internetautomar
that's how a lockup converter works.
it's a clutch inside the converter.
Normally a converter is just a fluid coupling and has some built in slip which allows the car to idle in gear. But when the converter is in lockup mode it becomes a more direct coupling like a stick shift, you can't idle in gear.
Did that make sense?
it's a clutch inside the converter.
Normally a converter is just a fluid coupling and has some built in slip which allows the car to idle in gear. But when the converter is in lockup mode it becomes a more direct coupling like a stick shift, you can't idle in gear.
Did that make sense?
. I meant how exactly it locks up. if it is in fact a clutch, then that could be the problem as well. Its possilbe that it functions, but not 100%.
01-16-2006, 04:38 PM
#20
Senior Member
Join Date: Jul 2005
Location: Townsville, Australia
Posts: 162
Originally Posted by 91WBSE
Ok the transmission shop tech. had a switch hooked up under the hood and all he did was start the car, put it in drive withe E-brake holding it, flipped the switch and the engine shut off supposedly cause the wheels are stopped and torque converter locked up. If you said that it has mechanical lockouts that prevent it from locking up in first gear, how would he have done this? If the car is sitting still in Drive, the transmission would be in 1st gear.
perhaps the guy at your shop did something similar, when he connected the switch for the lockup, perhaps he set the transmission to select only 2nd or 3rd gear?
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