slips in overdrive, hits all other gears fine
03-28-2007, 10:58 PM
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slips in overdrive, hits all other gears fine hey guys. i'm on my fourth rebuild, and have about had it with 4l60e's. the transmisson slips its *** off in overdrive, but only if i'm crusing down the freeway, like if i'm trying to maintain a certain speed. if i roll into it, it seems fine, and if i hammer on it it hits the 2-3 shift like a champ, but crusing this thing slips its *** off. any ideas? thanks guys.
Jordan
Jordan
03-29-2007, 12:09 AM
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i thought it was the converter lock up clutch, which is why i swapped my vig for my current yank... still slipping. i'm guessing a seal? seems to get better with rpms.
03-29-2007, 12:22 AM
#4
Did you change he seal on the input shaft, Also has PWM been disabled, Did you emove the encapsulated check ball from the end of the input shaft. What your describing does not sound like a transmission slip but rather converter clutch slip. Since you swapped converters and still have it you need to look for the underlying cause.
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03-29-2007, 12:41 AM
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check ball is still in the input shaft. not sure about the pwm being disablabled... mikey tunes the car. i appreciate your responses sir. the tranny was built the first time by a gm tech, then 3 more times by a supposedly reputable shop. i've got a nx kit i've been waiting to install for over a year cause my measly 400 rwhp keeps eating transmissions....
03-29-2007, 01:48 AM
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Stock tune commands 0% line (minimum real
pressure, not 0 PSI) at light cruise and the TCC
on a small diameter converter may just not have
the holding capacity, all the way into the load
before line is eventually bumped up. My old
converter couldn't.
A MAF that's sensing low airflow (load) will push
out the roll-on of additional line and make it worse
potentially.
Whether it's TCC slip or slip in gear can be seen
by the shaft speed ratios and the slip RPM numbers
in the scan tool.
pressure, not 0 PSI) at light cruise and the TCC
on a small diameter converter may just not have
the holding capacity, all the way into the load
before line is eventually bumped up. My old
converter couldn't.
A MAF that's sensing low airflow (load) will push
out the roll-on of additional line and make it worse
potentially.
Whether it's TCC slip or slip in gear can be seen
by the shaft speed ratios and the slip RPM numbers
in the scan tool.
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03-29-2007, 01:07 PM
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You might want to look at your Dynamic Cylinder
Air value at WOT (if you can use the TechII like
that) as an indication of whether you are getting
a sensible MAF reading; at about 5000RPM you
should see maybe 0.8 g/cyl at least, really more
than that with a cam. If below this I'd try cleaning
the MAF and relook at the g/cyl again. Just because
I see the K&N in your sig. Falsely low load values
can starve the trans of the pressure it needs.
Air value at WOT (if you can use the TechII like
that) as an indication of whether you are getting
a sensible MAF reading; at about 5000RPM you
should see maybe 0.8 g/cyl at least, really more
than that with a cam. If below this I'd try cleaning
the MAF and relook at the g/cyl again. Just because
I see the K&N in your sig. Falsely low load values
can starve the trans of the pressure it needs.
04-04-2007, 08:45 PM
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ok, no slip codes, 4th gear is comanded, all gov values stay constant, lock up clutch is holding (comanded lockup in 3rd, ran it all the way up, never unlocked) now what?
04-05-2007, 01:10 AM
#12
Hmm thats odd because if lockup was comanded and it slipped in and significant level it should still set a code 1870 componet slipping , Strange . Since you have a tuner can you put the car in lockup and observe the input or engine rpm verses output rpm or speed , If so post it and we can calculate the percentage of slip in overdrive
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04-05-2007, 01:55 AM
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that has to be it, the 4T80E in my Caddy's did the exact same thing. I guess I figured with a built 4L60E that it wouldn't do that, but then again the PCM controls the shifts.
