I was driving home today from work and traffic picked up from around 50 to 70 so I increased speed gradually but just enough to unlock the converter. once it unlocked it had no power and rpm's surged. first sign of any issue with my setup.

I let up on throttle and converter relocked and had full power. further down the road I bumped the throttle and half the time it would feel like something was slipping and other times felt fine. more throttle though more often I would get this effect.

at a full stop acceleration everything worked fine with normal driving. about 15 miles further down the road I started slipping in and out of lock up at a cruise around 60-70mph.

setup is a BMR racing lvl 3 4l60e with a circle D 3200 stall. I don't have any real abuse on this setup as its just a daily driver and I don't play in it really.

the only thing I've done to the truck lately was spot weld a small leak on my exhaust yesterday but if that caused electrical issues I think it would have surfaced sooner. I drove to the store and back sunday afterwards and to work Monday (50 miles) and half way back home (20 miles) before any issues. I don't feel at this point the slip is the trans but not sure.

 

any input anybody?

 

Need to get a scanner on it to see why it is falling out of lock up. Typically when it is locked up and feels strong, meaning you can ease into it and it does not slip - then it is tune related. And if it slips when you load it locked up then it is typically in the trans or converter - internal pressure problem. Typically....

But you can get a scanner on it to see if the computer is turning off lock up, if so then the computer is seeing something it does not like. If it is slipping and then tuning off the lock up, then we need to look at the trans /converter.

Hope that made sense.

Chris

 

thanks for the input. i was going to send you an email today. i have hp tuners so i'll look into what i can see with that first. i havent touched my trans tune in a pretty long time with no issues so i'm hesitant to believe its in the tune itself.

on a side note i work less than 10 min. from you guys but my truck is at my home in willis so getting it to you may be an issue if we get to that.

 

quick note after re reading this

initially there was no slip during lock up. the slip or lack of power transmission happened only with enough throttle to command the converter to unlock. a few miles further driving the lock up began slipping during steady throttle at cruise speeds. it was not disengaging lockup fully, it just felt like the lockup was slipping giving me 600-800 rpm changes and a surging feeling in the truck. without lockup engaged at those speeds there is alot more rpm difference than what i was seeing.

also after seeing this and getting off the interstate i had a chance to give more throttle at slower speeds where there wouldn't be lockup commands and with enough load the trans would slip. normal driving shifting still felt fine.

i havent had time to drive it anymore since i parked it.

i checked fluid level when i got home and it was right and fluid looked clean. the transmission temp was also ok.

 

Let us know what the scanner shows, pay attention to the slip numbers and the TCC percentage. That will let you know which one turns off first.

Chris

 

ok got a scan in. I didn't slip any until I got some temp on the trans. I didn't go far enough for lockup to start slipping but I did get slip when accelerating enough to downshift.

I found and used this config file. you can see starting at data point 5450 and again at 5530 I get a lot of slip. I didn't get any slip noticeable during the run until then.

 

do you have a better config file I can use that will show more information? i'm not versed on setting up config files.

 

one more note for events leading upto my trans issues.

one day prior to my problems I spot welded a leak on my exhaust. I dismissed this possibly leading to issues because I got several miles out of it before issues. it occurred to me this morning that my transmission really never got a chance to warm up until I got the problems. one drive was too short and the other was open highway at 5am so cold weather.

so with this I am wondering if I possible hurt some of my electronic (epc, ect.) with my welder. are these possible pressure issues giving me the sudden problems since the trans hasn't missed a beat until this came up?

 

Sorry, have not had a chance to open the files. Will try to get to them tomorrow. You want to monitor TCC slip and TCC duty cycle I think. And does it happen when you command it to unlock?

Chris