Torque Converter

[PPowers]

My torque converter locks up every time i put in drive whats the deal

 

[cerberusiam]

Need a little more description of the issue and some info on your truck to tell whats up.



The TC is supposed to lockup in drive but only when your up to cruising speed.



If your saying when you are stopped and you put it in gear it lugs the engine down and the truck tries to go, you have a bad TC. Its a common failure on some of these TC's.



If I was guessing I'd say you have an 06 truck?

 

[PPowers]

2004. 5 2500 48re P1740 code shows up it never disengages. Its like a manual now with no clutch pedal and shifter. its either the TCC or overdrive TCC lockup solonoids have crapped out.

 

[cerberusiam]

Does it actually kill the motor or just pull hard against the brakes?



The code could be from the TC going bad and the solenoids just not abl;e to engage. Either way its rebuild time.

 

[PPowers]

I have to put it in nuetral every time I stop other wise it wont disengage or down shift and shift it up through the gears from there. I new I shouldnt of bought an automatic.

 

[cerberusiam]

It could be other things but it sounds like the TC has locked up the sprag clutch on the stator. That is a weak point in the TC.

 

[PPowers]

It doesnt do it in reverse though. When I shift it up through the gears it unlocks when i go from 2nd to 3rd gear

 

[cerberusiam]

It doesnt do it in reverse though. When I shift it up through the gears it unlocks when i go from 2nd to 3rd gear

Reverse I am not sure about, once you are up to speed and rolling in the forward gears it will fine as thats when the sprag should be locking. I would replace the TC and go from there.

 

[rscurtis]

I'm sure you'll correct me if I'm wrong, but I don't think this is a stator related problem. A locked sprag clutch will not act like a locked converter, and will perform OK under acceleration. When cruising, it will not unlock and the truck will feel like you're constantly driving uphill.

 

[cerberusiam]

At cruise the sprag is supposed to lock the stator to the turbine and redirect the fluid flow for better TQ multiplication, ie. a tighter coupling. On acceleration or in gear there is no stall so the TC is in tighter mode already and will not allow the motor to rev into the power band to accelerate faster.



If the motor does not kill at a stop its probably not the TC clutch and it is the sprag. It could be some other thigns like a cracked case or bad VB but not sure what would cause those symptoms. By far the most common is the sprag on the stator.



I have had one partially start to go and it bogged the engine on acceleration but but was OK at an idle. The ones that locked solid I have just had described and thats what this is sounding like from his description.



Then again its internet troubleshooting at its best.

 

[PPowers]

So the sprag and TC is junk. one more question then unless i choose the gears myself it goes straight into 3rd and locks the TC right away when I put in drive. It does the same when I drop it into 1st then second when I hit 3rd it unlocks revs up and then locks again, could it be the solonoids and the TC at the same time. Its acting like a manual trans when the slave or master cylender is bad I cant remember which is which, the hydralic preasure bleads off and the clutch engages. This happend on my 2001 six speed a few years ago. Thank you for your help much appreciated.

 

[cerberusiam]

Its hard to tell the exact problem. About the only thing thats for sure is its in need of a rebuild.

 

[PPowers]

Yup thanks

 

[PPowers]

I was thinking of going with Goerend Ive known poeple with ATS trans that have had problems never heard of a problem with Goerend Trans.

 

[cerberusiam]

I was thinking of going with Goerend Ive known poeple with ATS trans that have had problems never heard of a problem with Goerend Trans.

Goerends, HTS, Garmons, don't think you can can go wrong with any of them.

 

[MoparDave]

Start with the simple stuff first, you may have a stuck overdrive & lockup solenoids or other VB problem. rscurtis explanation is accurate, the stator free-wheels when the turbine builds enough speed to return the oil to the impeller on its own. The stator is locked by design as the TC builds TQ when accelerating from a stop, oil needs to be directed back at the impeller to help build TQ. If it was the TC the problems lies on the lockup side. It does not happen in rev so this lead me to think its else where.

 

[wantabe351]

Did you ck the fluid level? Is it low,dark? Talking to a friend of mine who is a Dodge tech was talking about trucks stalling out when put in drive. This is the newer trucks and you didn't say what yr you truck was. What happens when cold there is not enough fluid pressure to release the TC LU (low on fluid,no stick reading)... Its a long shot but ck it out,and if its ok then the problem my be in the VB.....

 

[cerberusiam]

Did you ck the fluid level? Is it low,dark? Talking to a friend of mine who is a Dodge tech was talking about trucks stalling out when put in drive. This is the newer trucks and you didn't say what yr you truck was. What happens when cold there is not enough fluid pressure to release the TC LU (low on fluid,no stick reading)... Its a long shot but ck it out,and if its ok then the problem my be in the VB.....

Yes he did, 04. 5 truck, check the 3rd or 4th post.



Lockup is a solenoid that defaults to open and requires pressure to apply. The ECU controls when the solenoid allows fluid to the clutch. If you have low pressure it won't apply the clutch. Too low and the truck won't even move and he said it runs fine once its up to speed.



The solenoids rarely stick closed because they are spring loaded. Far more common is they don't work and no apply. The sprag clutch going out and locking the stator is a common problem. Either way it needs to come out and be opened up.

 

[wantabe351]

I dont think its the TC. . For if the TC is locked full time,it would also stall in reverse. . I dont have a fluid chart or trans manual at home for my truck to ck for the clutch applies,VB. . Check the LU circuit (fluid)... doesn't hurt to put a guage on the LU port on the trans to ck the pressure value...

 

[cerberusiam]

Its probably not the lockup clutch or it would be locked in reverse like you say. I asked the OP if it killed the engine and he never answered directly. If it was killing the engine and a stop sign it would essentially be undriveable and he indicated it was driveable once up to speed.



The TC lockup uses line pressure to apply the clutch. There is no port to test lockup apply presure as its all internal to the VB. It COULD be the lockup clutch dragging because of a VB failure, or, more likely the stator sprag is locked causing a very low stall condition. Either one would emulate the symptoms.