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Torque Converter Lock / Unlock Issues

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Gtxracer

Gtxracer

Posted
Posted

I'm hoping someone can help me out with my TC lockup issue, I'm at my wit's end. Truck is a 98.5 24v, only real modifications are a BHAF and Edge EZ. Trans was rebuilt about 100k ago with billet torque converter and full R&R.

I've been chasing a locked torque converter issue for months. After researching the issue I tried a number of different fixes. Flushed and filled the trans, pulled the valve body and inspected, replaced lockup solenoid, checked lockup spring, bypassed the trans cooler, and finally checking for AC noise. Upon checking for noise, I used a cheap DV and came up with 30V AC. Used a Blue Point Pen-Probe style DVM and the AC voltage fluctuated and was well over 0.1VAC. Replaced alternator with O'Reilly reman and same readings. Returned that reman and put in the existing alt.

Removed the 140A fuse for the alternator and issue remains. Seperated the ground from the loom on the back of the alternator and covered with aluminum foil. Issue remains. I tried adding another ground from the battery to the body of the alternator, no change. I then tested the system, with the 140A fuse for the alternator removed, and there is still 2.48V AC at the bridge of the fuse and fluctuating at the battery terminals. What is going on??? How is there AC noise when the alternator fuse is removed?

Couple more details - the TC will lock and unlock. Not on the highway, it's usually fine there. When cold, it behaves normally. After warming up, the TC will lock. It also will unlock randomly and stay unlocked for a little while. If I turn the truck off while it's unlocked, then start again, the TC will usually lock. Is my PCM toast? ECM? Did my alternator fry everything already? The VP44 and lift pump were replaced about 40k ago. Help!

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Bryan

Bryan

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Posted

Got my new alternator today.  Took a Bosch off and the replacement was a Denso.  After replacing the alternator, the test result was 0.00 to 0.015 VAC.

I will road test tomorrow.  I am pretty sure that solved the problem.  I did check the alternator brushes for the field and they were pretty well worn along with a lot of scoring and grooving on the slip rings.   Not sure if they contributed, but I am sure that didn't help anything either.

After 2 days of driving, the TC has stayed locked.  Looks like the problem is solved.  Time will confirm my results.

Thanks moparman

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Bryan

Bryan

Posted
Posted

Pepsi71Ocean found that a bad set of slip ring brushes can create high AC noise issues as well so it might of been that as a cause too.

I am going to see if I can find a rebuild kit for the alternator.  Not worth paying the shipping costs for the core charge refund. 

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Bryan

Bryan

Posted
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On 10/21/2015, 7:02:15, Bryan said:

After 2 days of driving, the TC has stayed locked.  Looks like the problem is solved.  Time will confirm my results.

Thanks moparman

It's been a couple of weeks, and everything is holding.  No instances of the torque converter unlocking.

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Dieselfuture

Dieselfuture

Posted
Posted
On 11/1/2015, 8:50:53, Bryan said:

I got it from http://allmoparparts.com/amp-parts/#parts

Make sure you have your VIN handy, they did check mine to make sure it would work on my truck.

According to this website there is only one alternator available fro our truck http://allmoparparts.com/amp-parts/#parts I'm guessing you got same one? This  part #5104772AA  So the one you got from this website was a Denso and now they want your core or $163.85 is no core and shipped to your door?

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Dieselfuture

Dieselfuture

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Posted
On 10/21/2015, 9:35:41, Mopar1973Man said:

Pepsi71Ocean found that a bad set of slip ring brushes can create high AC noise issues as well so it might of been that as a cause too.

That is correct Pepsi71Ocean is right and I just confirmed it. I rebuilt my alternator last year and put new bearings, diode pack and new brushes, I did not changed slip rings and didn't realize just how worn they were till the other day. I decided to figure out why after rebuilding my alternator I still had around 0.05vac at idle and if revved up i could get it over 0.1vac. So I tried to use a small flat piece of hardened steel to get the edges rounded off and get grooves a bit smother (while it was on the truck and I could start it and get to slip rings while engine was running I was milling slip rings) , thinking it would be a lot better. After wasting about half an hour put it all back and my vac jumped from 0.05 to 0.12 at idle and 0.23 revved up. Maybe after it would all seat in new place it would come down but considering slip rings were most of the way wore, I went to local alternator place and got new slip rings for $10, took it all apart soldered it all back in place and what do you know 0.07-0.08vac on start up, then went for a ride about 10ml checked it again 0.03-0.05 vac and if I revved it up it didn't go past 0.05 where before it would get over 0.1 sometimes. So i'm hoping after some time when brushes wear to slip rings it would be down to 0.01-0.02vac. But the whole point of this, is that messing with slip rings and brushes does affect VAC. Even though diode pack should take care of it. Hope this wasn't too confusing. Tried to attach some pictures but wasn't able too. 

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Hawkez

Hawkez

Posted
Posted
3 minutes ago, Dieselfuture said:

That is correct Pepsi71Ocean is right and I just confirmed it. I rebuilt my alternator last year and put new bearings, diode pack and new brushes, I did not changed slip rings and didn't realize just how worn they were till the other day. I decided to figure out why after rebuilding my alternator I still had around 0.05vac at idle and if revved up i could get it over 0.1vac. So I tried to use a small flat piece of hardened steel to get the edges rounded off and get grooves a bit smother (while it was on the truck and I could start it and get to slip rings while engine was running I was milling slip rings) , thinking it would be a lot better. After wasting about half an hour put it all back and my vac jumped from 0.05 to 0.12 at idle and 0.23 revved up. Maybe after it would all seat in new place it would come down but considering slip rings were most of the way wore, I went to local alternator place and got new slip rings for $10, took it all apart soldered it all back in place and what do you know 0.07-0.08vac on start up, then went for a ride about 10ml checked it again 0.03-0.05 vac and if I revved it up it didn't go past 0.05 where before it would get over 0.1 sometimes. So i'm hoping after some time when brushes wear to slip rings it would be down to 0.01-0.02vac. But the whole point of this, is that messing with slip rings and brushes does affect VAC. Even though diode pack should take care of it. Hope this wasn't too confusing. Tried to attach some pictures but wasn't able too. 

Hopefully you are able to get pictures loaded, I'd be interested in seeing them.  Has anyone written an article on rebuilding an alternator? 

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Bryan

Bryan

Posted
Posted
On 11/4/2015, 11:38:01, Dieselfuture said:

According to this website there is only one alternator available fro our truck http://allmoparparts.com/amp-parts/#parts I'm guessing you got same one? This  part #5104772AA  So the one you got from this website was a Denso and now they want your core or $163.85 is no core and shipped to your door?

The price is plus a core charge.  $50 core charge is added at checkout.  Shipping from here back to the east coast doesn't make it worth sending the core back for me.

On 11/8/2015, 8:12:07, Dieselfuture said:

I tried to in one of my posts, but i'm not a good article writer. I have few pictures of parts for Bosch alternator that's the one on my truck.  Tried loading pictures and the message I get is ( There was a problem processing the uploaded file. -200 )

Maybe you could list the part numbers and where you go the kit.

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  • 3 weeks later...
balsip

balsip

Posted
Posted (edited)

I have been absent on this for several years but decided to look at the the design of the 2010 APPS since Dodge is bound to fix the problem in the newer design.  Looking at page 14-125 of 2010 FSM they mention two APPS on the accelerator pedal with one APPS 1/2 the voltage of the other.  Then the circuit diagram on page 8W-30-24 shows the two APPS wired to the ECM.  I could not find the Theory of Operation on this but I guess that they have a "differential amplifier" in the ECU that takes the difference (differential amplifier) of the two signals such that equal noise on both signals cancels out. They use the 1/2 voltage route since a MINUS 5 Volt supply would otherwise be required for the second APPS. The noise would be equal on both signals for any ground resistance but usually twisted pair wire  is used so that any induced noise is also exactly equal and also cancels out. Telephone companies  have all used that for 100 years or more.

2nd generation owners obviously can not go to this extent so we are limited to noise filters, wrapping wire bundles in aluminum  foil,  adding beefier grounds, and making sure alternator diodes are all good. Whatever works for your situation. I use the noise filter(2010) and I had to double my capacitor value after four years to make it work again for me(2014).

I could not see the APPS signal passed onto the PCM (transmission shifting) as hardwired so I assume the Can Bus and processors are  faster so that it cal be passed on digitally over the serial link. Dodge designers seemed to be more worried about ground noise than induce crosstalk - no twisted pair. With no need  for a down shift cable to the 68RE  all electronic transmission they got rid of all cables - throttle and downshift.

Edited by balsip
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CSM

CSM

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If you have to put that much capacitance, you have voltage issues.  Ground, charging sys, somewhere.   After I redid my grounds and alternator I have had zero shifting or lockup issues.

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pepsi71ocean

pepsi71ocean

Posted
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After fighting Napa bull carp I dropped the money for a new denso alternator from dodge. 

The part number is 5104762AA and the tc issues are gone.  However, my passenger side is reading .05-.06vac and the drivers side is .02-.03vac.  I'm going to have to further this with Mike. 

The other chase right now is the vdrop testing of my ground cables. The passenger was .07vdc but the drivers side was .184vdc

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CSM

CSM

Posted
Posted (edited)

Pepsi, 

I think there is also some gains in replacing the + lead from the alternator to the battery with something thicker.  You may not see this at idle in your driveway, but on a cold winter day after a bad start and long idle with the lights and heater grid going, a resistance there could easily make some noise within the system.  

The stock lead is not "diesel" sized, IMO, but I haven't done any math to prove it.

Edited by CSM
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  • 3 weeks later...
Redfishin321

Redfishin321

Posted
Posted

Hi everyone, im new here as a member but ive been following this topic for a while cause I too am having lockup issues, I first had it almost 3 years ago.. I got the BD noise isolator and that fixed it until earlier this year, I cleaned all grounds and replaced my terminals and the issue went away for about another month, then it came back, this time i replaced my alternator with a BRAND NEW one and it was fine for about 3 weeks, then it came back, i reset the tps and it was fine for about 2 weeks, then yesterday it started back up worst than ever.. i am at such a loss!! Tomorrow morning im taking it to a local auto electic shop to have them test the alternator specifically for diode failure. Maybe this new one went bad? If it turns out to be good im at a loss of what to do.. My truck is a 98.5

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