TG02Z71

iTrader: (2)

I posted this yesterdy and today in the truck section with no answers yet, you guys know anything about this and what may be causing it to throw this code?
My trans gets hot fast and feels like its slipping and the fluid has a SLIGHT burnt smell.

It is really difficult just to get up to 40mph without gassing it and heating it up even more.

Could my trans have a sticky solenoid or something?
I grasping at straws here so bear with me.

I posted allot more info on the truck drivetrain section, but pm me if you might know what this problem is from.
I have to get this baby rollin, its my daily driver.

Trouble code seen through Predator diagnostics.
P0741 Torque Converter Clutch Circuit Performance or Stuck Off

jimmyblue

iTrader: (11)

I had a problem like this last summer, I think I got this code.
If the converter slips too much when "locked" then the PCM
will give up locking it. High trans temps make TCC slip worse
in my experience. This can turn into a runaway situation; did
for me anyway. What converter type is this? Do you have a
trans cooler? Does this "Nelson tune" comprehend the turbo
being there? What I've seen in chasing down my own slip problems
is, the PCM is commanding 0% line pressure at cruise and starving
the TCC despite there being a nonzero load. Unfortunately the
software I use, doesn't have anything to do with the line% vs engine
load, so I have to back-door it by the force motor current (less, =
more line pressure and then the TCC has something more to work
with). But this is a lame-*** crutch I think. Anyway, if your STS kit
has you making way more torque than GM figures, this would only
be worse.

TG02Z71

iTrader: (2)

Nelson tuned the PCM for the turbo, I also bought the turbo kit from him. Not sure what all the parameters are that he set. I'm currently trying to get a list of all the parameters that he modded for me to make the turbo work.
My truck has a stock tranny cooler and I think if it was not for that and the fact that it was 24 degrees out the day this happened my trans would be toasted right now. I'm most likely getting a new PCM from Allen at Nelson soon.

Thanks for the feedback man, your the only one who even responded, I'm starting to think I'm invisible on this board.

jimmyblue

iTrader: (11)

Well, I would make sure they understand the slip issue,
ask them if they can either bring the line % up faster
relative to load or, if you get the telephone equivalent
of a blank look, ask them to lower the force motor
current in the lower line% columns somewhat. That would
at least compensate some for the added torque.

Didn't see whether you have an aftermarket converter.
If so this could be part of the problem esp. if it's a small
diameter one meant for cars.

TG02Z71

iTrader: (2)

I still have the stock converter and have never had this slipping issue before or after the STS install.

In fact my truck was basically bone stock except for intake "FREE' mods that I did.

At this point all I have done is install the STS base kit along with the updated PCM to make it run right.

The STS kit was installed about 4 weeks ago, worked good the first 3 days, then after I got it broken it, it stared overboosting up to abot 10psi.

Its supposed to be 5-6 psi max on the base kit. I've taken apart the wategate and foung nothing really physically wrong with it.
From what STS tells me I have the right spring (ren in color for base kit).

Finally got a boost gauge in 2 weeks ago and confirmed my thoughts on over boost. I did have to take it up a few times to see, but I was very careful. Rolling into it a couple of times , then flooring it to see the gauge readings.

Long story short, I've been driving it very conservatively for about 3.5 weeks because its overboosting and have not ben able to find out why.

I just wonder if the few times I've floored it has caused all this to happen.

How and why would my trans work and have enough line pressure for 4 weeks then just get weird?

Could a vacum leak of some sort cause all this?
I seem to get some good vacum reading off the gauge at idle, about -15/-18.

Thanks again for the response.

jimmyblue

iTrader: (11)

I think you may have a problem with the high boost
maybe going "over the top" on the MAP sensor and
not registering? This might (I am no turbo expert) make
the PCM mis-compute the load value. But at part throttle
I would not expect to see the full pressure inside the
manifold?

If you slipped the TCC under full load for a while then
that could put a glaze on it. But I would have expected
full throttle to be unlocked. Don't know what your tranny
tables looked like stock, or look like from Nelson.

My converter started off OK, commenced to slip and howl
after a few hundred miles with the B&M juice, got better
but not completely with a flush-out and has been showing
progressively more slip (which I push back with progressively
higher line pressure at the lower commanded line end). But
it's to the point that I'm not really comfortable with any more.
Once it takes a notion to slip, I think it's only going to get
worse (not likely to unglaze).

Look at it this way... maybe you've found your next mod.
Make that your next two... a good truck performance
converter (with a solid-*** TC clutch, not like the small
diameter car ones), and HPTuners.

TG02Z71

iTrader: (2)

They may be glazed already, my fluid smells a little burnt now.
I'm not driving it anymore until I get my new PCM and wastegate spring replaced.

Ragtop 99

iTrader: (7)

you need to log your tranny temps. Have you changed your fluid and filter? Make sure there is nothing obstructing your cooler. As Jimmy said, even at low TPS you may be making more torque than GM anticipated.