Archived Torque converter lock/unlocking problem

[BSnyder]

I'm currently having torque converter lock-up problems. I've researched the archives and I'm methotically trying to work through the known issues. Any and all help would be greatly appreciated. Recent changes to my '99 4x4 automatic dodge are 315 pro comp tires, a new thermostat to replace a stuck open one (no heat), and a new TPS to replace one with a hick-up that kept throwing codes. So far, I cleaned the battery cables, I'm in the process of recalibrating the new TPS "again" and I'm cleaning all the ground straps that I can locate. The torque converter begins to regularly go in and out of lock-up between 40-55 mph and above 55 remains unlocked with higher rpm's. I just had the transmission serviced, new filter and fluid with the transmission mechanic adjusting the line pressure eight more psi and minor adustments to the first bands no other seen problems. His scan tool shows the computer is calling for the trans to lock and unlock as we are driving which is what it is doing and he doesn't think the electronic switches in the valve body are bad, but is not sure. My transmission has 167,000 miles on it. Are there any computer reflashes that may need to be done or should I consider a torque converter replacement and valve body shift kit upgrade anytime soon due to the milage? My transmission doesn't seem to slip and the lock-up is the only issue known. I'm trying to head off any major repairs before they happen.



Thank you.

Brad Snyder

 

[Bob4x4]

There is a flash that addresses your issue. It may or may not solve it on your truck. As the truck ages it will produce more electrical noise. There are many things that you can do to help sheild these by replacement parts and mechanical sheilding but you may save yourself some time by ordering a noise filter from DTT. Diesel Transmission Technology - DTT Performance Diesel Transmission and Power Accessories



Bob

 

[PetesonM]

bypass

You can also bypass the ecm and go from the apps to the pcm. The "elect Noise" seems to interfear with the signal there or in the wire loom. I ran a by pass wire (route it outside the loom) over 2 yrs ago no problems. other fix is main - @ batt or on block. cummins painted everything but dodge didn't clean it well during assembly clean motor - then reassemble. good luck

 

[TSRAM]

You can also run another ground wire from one of the mounting screws for the pcm back to the firewall where the pass. side battery ground is connected.

 

[PhilLewis]

Insulate the ground behind the alternator

BSnvder,

I had the same problem over several thousand miles. I don't know the post but I learned that insulating and /or rerouting the ground wire that runs from the passenger side batt behind the alternator can correct your troubles. I bought some aluminum duct tape (2" wide?) from home depot to shield the wire and routed the wire over the top of my alt instaed of behind it fixed the problem. 10K? so far no issue. Supposedly the elec noise from the alt messes with the signal controlling the TC valve. Many miles ago I also bypassed the harness with the TPS wireing but the problem returned quickly. Hope this helps.

 

[docjara]

How do you tell if your TC is not locking. I can not feel the difference. I know it is not locking in stop and go traffic because that is when the temp is rising.

 

[B.G. Smith]

How do you tell if your TC is not locking. I can not feel the difference. I know it is not locking in stop and go traffic because that is when the temp is rising.

The T/C should lock above 45 mph in OD and above 35 mph with OD off, you should see a 500 rpm drop when the T/C locks, with 3:54 gears you should be turning about 1900 rpm at 70 mph with T/C locked in OD. bg

 

[junkerman]

torque converter

I also have same problem . Dose anyone have problem with cruise control at same time?

 

[Huff N Puff]

The T/C should lock above 45 mph in OD and above 35 mph with OD off, you should see a 500 rpm drop when the T/C locks, with 3:54 gears you should be turning about 1900 rpm at 70 mph with T/C locked in OD. bg

I'm pretty sure lockup occurs after 35mph and you almost can't feel it,its OD that drops the rpm 500 or more.

 

[SHull]

I am in the process of removing the apps wires from the wire bundle that run to the ECM. I hope this will do the trick on my 02. It sure is a pain in the butt to seperate these wires from the rest. I had bought a noise filter and put it on the orange and light blue wire pin 23 on the PCM and it didn't do anything.

 

[fox]

I also have same problem . Dose anyone have problem with cruise control at same time?

Your brake pedal is bouncing.

 

[Huff N Puff]

Its important that you check the voltage on the ground

I am in the process of removing the apps wires from the wire bundle that run to the ECM. I hope this will do the trick on my 02. It sure is a pain in the butt to seperate these wires from the rest. I had bought a noise filter and put it on the orange and light blue wire pin 23 on the PCM and it didn't do anything.

Of the APPS, if the ground is poor the APPS voltage will be all over the place. Its best to do a voltage drop. Set your volt meter to the lowest voltage setting connect the one volt meter lead to the Neg. battery cable and the other to the APPS ground if its reading more than 60millivolts the APPS ground is poor. Best to do it with the truck running.

 

[JDiepstra]

I can't exactly speak about a 99 auto, but from what I know about the auto trans in my 04. 5, it sounds like your transmission is functioning normally.



The torque converter will lock up on my truck at 50 mph or so, depending on throttle input. It will not lock under heavy throttle. The computer does this to prevent the transmission from slipping a locked converter, causing damage. I imagine this is why your TC remains unlocked at high rpm's. It is supposed to do that.



As already asked, how do you know when it is locking and unlocking? It is almost an unfeelable event as far as I have seen while monitoring it on my Edge Juice w Attitude.



People who say that the rpm's drop 500 when the TC locks are not correct, at least not on a 3rd gen, and probably 2nd gen as well. The rpm drop comes from gear changes and overdrive, not TC lockup.



Also, the TC is supposed to unlock below certain speeds, otherwise the truck will bog or stall out.



There is a lot of misinformation on TC lockup out there so talk to someone who has a reputation for knowing what they are talking about.

 

[SHull]

Update I spiced into the apps ground (black with yellow) and grounded apps and ecm to the neg on the battery. Then reset the apps nothing changed. Also bought two new batteries the others where the orginals reset apps again. Thought I had the problem taken care of the shifting was smooth for the most part. But every now and then it will unlock/lock going into 3rd and into OD. The problem is not as bad as it was before it is not as consistant but still happens maybe 30 percent of the time. Like I said I installed a filter,( not the DTT or BD filter ) added ground from PCM to neg on battery, seperated the apps wires from wire loom to the ecm, cleaned the grounds, replaced batteries, and grounded the apps. Something is going on with this truck. This is frustrating all this time I have put into this and haven't got it taken care of.



02 Ext cab

 

[Popiol]

check speed sensor on trany, that worked for me.

 

[SHull]

Thanks for the advise I will try that. Next ? how do you ops check the speed sensor.



02 Ext cab

 

[Bob4x4]

If you still have the original software from 99 get it flashed. Dealers normally get 1 hr labor to do it.



Bob

 

[Bob4x4]

I have also never seen a speed sensor give these symptoms and no others. On newer trucks out put speed sensors can do a few similiar symptoms.

 

[JDiepstra]

Update I spiced into the apps ground (black with yellow) and grounded apps and ecm to the neg on the battery. Then reset the apps nothing changed. Also bought two new batteries the others where the orginals reset apps again. Thought I had the problem taken care of the shifting was smooth for the most part. But every now and then it will unlock/lock going into 3rd and into OD. The problem is not as bad as it was before it is not as consistant but still happens maybe 30 percent of the time. Like I said I installed a filter,( not the DTT or BD filter ) added ground from PCM to neg on battery, seperated the apps wires from wire loom to the ecm, cleaned the grounds, replaced batteries, and grounded the apps. Something is going on with this truck. This is frustrating all this time I have put into this and haven't got it taken care of.



02 Ext cab

Am I the only one thinking that the TC should not be locked going into 3rd and overdrive? It is supposed to unlock during shifts. Not to mention that a stock TC should not be locking until 4th gear in most cases anyway. 2nd gear lock up is unheard of AFAIK unless you have a lock up switch or a trick valve body or something. Most of what I am hearing still sounds normal.



Again, where are you getting your locked or unlocked info?

 

[SHull]

Ok it feels like the truck cuts out for just a split second before it changes into 3rd and 4th. i promise it isn't normal. Bottom line it is doing what everyone elses is doing on here. Some of them are calling it torque converter lock/unlock. If that isn't what it is then what is it?



stock 02 Ext cab