JURB6006 wrote:
Thanks again Bob, but how did you get the meaning of those codes off
Google ? I
just tried it and pretty much didn't get crap.
Try the search phrase "DCT P0740"
that should pull up this page among others:
http://www.c5forum.com/ayc/1997dtc.php
I got all kinds of things, but nothing that defined the codes.
Anyway, now I'm somewhat at a loss for specifics. How the heck would
it know
about other shift solenoids, as well as the TCC one ? The codes, 1-2
shift, 3-2
shift and TCC, all at the same time ?
They may not happen all at the same time. Once a code sets, it stays.
Now the question becomes how are they detecting these faults, are there
mechanical state switches in the tranny or is this all coming from an
error
comparing the crank to the VSS, which incedentally I wonder exactly
how they
deal with that, being a 4WD. I guess they would need a secondary VSS
on the
transfer case output for the speedo, or does it just "know" ?
Many ways. The engine knows its RPM. It has the VSS signal. And i
believe there is a signal on the tail shaft for output rotation. It just
does the math. It figures on what gear it commands, figures the ratios,
and goes from there. Probably looks at the internal pressures too.
With these codes now, remembering the symptom:
Reset computer runs fine, afterwhile starts taking off in second and
no passing
gear. When it gets hotter it will no longer shift into first even
manually.
I wonder if the computer is reading the other two codes because of
being in the
limp home mode. Even so, how could it differentiate between anything
involved
at times when the TCC should be applied. When the TCC isn't applied
how would
it know the stall rate of the torque convertor ? Is their math that
good that
they can do it from the MAP or MAF along with the other engine
values ? That's
almost scary (lol).
Did you take the trannie electrical plug off and inspect it closely????
Did you measure the resistance of all the solenoids at the trannie plug
and directly on the solenoid?
I say fairly assuredly that the TCC should not be applied in anything
but high
gear, wouldn't you agree ? There is one possible fact not known
yet,,,,,,,,, is
it POSSIBLE that the TCC is supposed to engage in every gear because
they used
a bit of a different design of convertor, like one with nice high
stall, but
need the TCC because it'll overheat ?????
On the older cars, this was true. On some of the newer ones i am not so
sure. When TCC slip gets much above 200 rpm difference, its sets the
code. (when it knows the TCC is engaged). If the TCC was grossly
overheated, it will turn color. There is a thin strip of friction
material that the TCC uses for TCC lockup. The TCC will work normal
otherwise.
www.phoenixtrans.com/html/lockuplowdown.pdf
(assuming the rest of the trannie is ok)
This comes up because now I remember that the thing was picked up out
of town
and during the trip it pushed out some fluid. It had to have been
overfilled
because it wasn't real low when it got home. I wasn't on the trip,
but I heard
there was quite a bit. Was it expansion, or maybe the torque
convertor started
cavitating ?
Well, if you lost fluid and your level is ok, you definitely were
overfilled. My relatives windstar puked when it got too hot due to VSS
failure. Not a good thing for the trannie.
Bob
A penny for your thoughts, hell I'll double it !
Thanks again
JURB
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