TC Lock-up issues

[DogramTD]

TC wont lock up with the mystery switch anymore, and worse, when the EB engages it has almost no effect on braking the speed; It will engage, drop the RPMs and open back up all within 2 seconds. With the TC unlocked the EB is worthless which is what leads me to belive this is the issue.



So is the lock-up solenoid bad or the TC... ANyone had this issue? Ideas, suggestions, opinions?



Also, new turbo soundin a little funny, and not building much boost. I'm hazing on light throttle and when I was trying to listen for a "wierd noise" i revved the engine and it stumbled at the top end almost like it had a govenor interrupting it... Never experinced that before... Ideas on that?

 

[JLandry]

Does the transmission otherwise shift normally (including TC lockup) when not using the "mystery switch" or exhaust brake?



John L.

 

[DogramTD]

it shifts normal but hard to tell if the tc is locking up since i was either in traffic or strong cheyenne wind...



usually when the tow/haul is on and the EB switch it activated it changes the shift parameters and locks the TC much sooner than normal; its not doing that anymore either.



Still has the stock converter clutch/overdrive solenoid too.

 

[JLandry]

You might try checking for diagnostic trouble codes with a good code scanner and see if anything comes up. Transmission trouble codes won't trigger the check engine light.



John L.

 

[cerberusiam]

Check for codes with the key on-off sequence first and see what it tells you. Performance on the colenoids will set codes and frequently CEL's if it is bad enough.



If the TC won't lock and you can't feel it even in TH it could be solenoid, TC, or dropping pressure to the lockup clutch. If it feels like it starts to lock then free wheels with the EB it could any one of them.

 

[DogramTD]

Check for codes with the key on-off sequence first and see what it tells you. Performance on the colenoids will set codes and frequently CEL's if it is bad enough.



If the TC won't lock and you can't feel it even in TH it could be solenoid, TC, or dropping pressure to the lockup clutch. If it feels like it starts to lock then free wheels with the EB it could any one of them.

Thats what it is doing, feels like it wants to brake then free wheels with the EB. What would be causing pressure to drop to the lockup clutch? Front pump?



Checked for codes and I had an overboost code and low oil pressure code. The Overboost makes me wonder because I did just change the turbo to the ED 63/68/14 and removed the boostfooler, but I soldered in a 150 ohm resistor between the leads to the WG solenoid... so wouldnt think that would happen unless the MAP is still sending the signal due to higher boost levels; maybe I should put the BF back in.



The low oil pressure is just a side effect to the on going saga of wondering WTF is going on with the initial morning start up oil pressure build issues. havent been able to diagnose for the last 40K miles niether has the stealership... heck they tried to tell me it was sludge in my pan causing it... nope, I change my oil every 3K mi w/valvoline PB and use donaldson, baldwin or FG filters. That one drives me NUTS!



Taking it to the dealer tomorrow to have them run the STAR scanner on it, tell me what they find

 

[DogramTD]

Update: Tuned the truck back to stock and took her for a drive. First drove slowly up and down the driveway while it was cold and engaged the TC thru the Mystery switch, i could her and feel it wanted to do something just not much. So i took it down the road, turning MS on/off still feeling a very slight engagement. Sped up a little and let off to engage the EB, same thing, initial grab then free wheel. So i stopped at the stop sign and turned the MS on... the RPM's dropped 50; not even a full 100 rpms and it feels like someone bumped the truck with their shoulder as they were walking by...



So it sounds like the solenoid is working abd we are down to the TC or loss of pressure to clutch... would'nt the loss of pressure be caused by the TC as well?

 

[Bob4x4]

05 is still drb

 

[DogramTD]

What does DRB mean?

 

[Bob4x4]

That is the oem scanner for the 05 ..... not star scan

With a 500 hp potential your truck has, the ms is risky,not sure if you realize this

or even what t/c you have. There are few people that have a perfect record when using a toggle switch to control lock-up. Electronic controls cost more but are much safer to use on a daily driver. I wonder how many trans builders would warranty a trans with a M/s on it. None that I know. Just too much risk of taking out the converter. With out using a pressure gauge being used in the diagnostics it's all just a guessing game. I would recommend taking it to a shop familiar with your mods. Not many will recognize your BD tow lock

 

[DogramTD]

TC is stock, i dont use the MS too often and when i do, i ease out before engaging; never flip on when the pedal is eating the carpet. Mainly installed it to compensate for the shortcomings of the stock converter. I didnt realize the Star scan isnt used on the 05, I am looking to log all events on the engine cause im a lil concerned over the injectors as well even tho they are new. Alot of rattle and some haze even at stock... I think its an elevation thing tho because I came from the Cali coast to cheyenne, a 6000' elevation diference.



Still sounds as if the TC is going out although its wierd that it would still shift/drive normal if it was.

 

[Bob4x4]

The stock torque converter clutch was never designed to be used the way you were using it. Add in your additional power and voila. Toasted tcc. Like I said earlier you won't find any trans builder to recommend doing it the way you did. Buy a quality tc ,valvebody and build the trans for the power and weight

You have. There are no cost efective short cuts. Good luck on your build

 

[cerberusiam]

So it sounds like the solenoid is working abd we are down to the TC or loss of pressure to clutch... would'nt the loss of pressure be caused by the TC as well?

Sounds like the solenoid is working while the apply piston is warped and not sealing, that is a typical failure under hard use and\or extra pressure on a stock TC.



The lockup can fail for a multitude of reasons and the rest of the trans work perfectly, given the failure does not introduce FOD into the trans. Its an add on feature not integrated so not essential for operation.

 

[DogramTD]

Brought it into the dealership for diagnostics, they couldnt get their scanner to connect with the TCM, they think it is because of the BD tow-loc i have on there; but agreed there is definately a problem. So I took it to a recommended trans shop in town to try again. . funny they had no issues communicating w/the TCM. He did see where the command was given to lock up although it seemed to be a little late... he thought it should be at a lower speed. When the command was given nothing happened. seems to be the TC I am just hoping it didnt introduce FOD as Cerb mentioned. I hear most of this will get caught up in the coolers and to make sure of a good flush before reassembly.



More symptoms... this morning driving to work on I80, usually cruise set at 75 is approx 1800 RPM at about 5-7 lbs boost; this morning it was 21-2200 RPM with 12-15 lbs boost. Usually my trans temp guage doesnt move; this morning it was up to 150-160*



So thinking I will order triple disk from goerend and probably a VB as well... any suggestions?

 

[Bob4x4]

Brought it into the dealership for diagnostics, they couldnt get their scanner to connect with the TCM, they think it is because of the BD tow-loc i have on there; but agreed there is definately a problem. So I took it to a recommended trans shop in town to try again. . funny they had no issues communicating w/the TCM. He did see where the command was given to lock up although it seemed to be a little late... he thought it should be at a lower speed. When the command was given nothing happened. seems to be the TC I am just hoping it didnt introduce FOD as Cerb mentioned. I hear most of this will get caught up in the coolers and to make sure of a good flush before reassembly.



More symptoms... this morning driving to work on I80, usually cruise set at 75 is approx 1800 RPM at about 5-7 lbs boost; this morning it was 21-2200 RPM with 12-15 lbs boost. Usually my trans temp guage doesnt move; this morning it was up to 150-160*



So thinking I will order triple disk from goerend and probably a VB as well... any suggestions?

Your truck does not have a TCM,the trans control is in the PCM along with the engine controls,sounds like the dealer wanted to steer clear of your truck possibly not wanting to deal with your add ons

 

[SWithrow]

Sounds like you TC is toast. When mine went out I installed the lock-up switch and tried to lock up the TC while stopped and in drive and nothing happened. I ordered a Goerend TC and installed a TransGo shift kit, all is great now.

 

[DogramTD]

Thanks for the correction Bob, yes PCM; i get to talkin trucks and mind goes a million MPH. And yes, they did want to steer clear of it, requested I return the wiring to stock and bring it back.