4l60e, slipping in overdrive?
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TECH Regular
Joined: Mar 2005
Posts: 409
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4l60e, slipping in overdrive? i got a prob. with my auto transmission in my 00 z28. itll shift just fine, untill it goes in overdrive. when it does itll start to slip, so when it does, i take it out of overdrive, then shift back into it, and its alright for a while. if it starts to slip, sometimes ill stomp the gas and make it shift down by it self, when i do that, 2nd gear hits so hard that itll chirp the tires. im thinking it might be the tourque converter, but im not sure. im really lost on this one. any thougts, have anybody else experianced this?
4l60e slipping in od its not the converter because you said its fine in the other gears.my first reaction would be band but you said it barks in 2nd.im thinking maybe the shift sol. thats on in forth or maybe the input sprag that should be over running in the od range is getting ready to lock up. 
call chuck at finish line transmissions..flt is running a 15% off special this month.looks like a great deal!1-630-350-7776 
call chuck at finish line transmissions..flt is running a 15% off special this month.looks like a great deal!1-630-350-7776 Last edited by FLT; Jan 17, 2006 at 09:01 AM.
Originally Posted by cablebandit
are you sure its not the lockup in 4th slipping? If so, converter lockup clutch could be gone but very unlikely if you are on a stock converter.
Misfires will make the PCM unlock the converter.
Presumably you'd see the flashing SES but maybe
not. Misfires might be affected by load (4th vs
3rd).
Now, I've been having a similar sounding problem
recently, the lockup will engage fine/normal
sometimes, but a couple of minutes down the
road it'll flare back to unlocked, then relock,
or sometimes just not engage at cruise for a
while and then (with speed & TPS unchanged)
just decide to lock up. Looking at the scanner
this appears to be the PCM's doing, the TCC
Mode and the TCC action are in step but what
the tables command, is not always done.
So I'm scratching my head about what might
make the PCM decide to not do what I tell it,
at seemingly random times. Other than misfires,
which are logging zeroes in my case.
Presumably you'd see the flashing SES but maybe
not. Misfires might be affected by load (4th vs
3rd).
Now, I've been having a similar sounding problem
recently, the lockup will engage fine/normal
sometimes, but a couple of minutes down the
road it'll flare back to unlocked, then relock,
or sometimes just not engage at cruise for a
while and then (with speed & TPS unchanged)
just decide to lock up. Looking at the scanner
this appears to be the PCM's doing, the TCC
Mode and the TCC action are in step but what
the tables command, is not always done.
So I'm scratching my head about what might
make the PCM decide to not do what I tell it,
at seemingly random times. Other than misfires,
which are logging zeroes in my case.
On The Tree
Joined: Mar 2003
Posts: 137
Likes: 1
From: Texas
Originally Posted by jimmyblue
Misfires will make the PCM unlock the converter.
Presumably you'd see the flashing SES but maybe
not. Misfires might be affected by load (4th vs
3rd).
Now, I've been having a similar sounding problem
recently, the lockup will engage fine/normal
sometimes, but a couple of minutes down the
road it'll flare back to unlocked, then relock,
or sometimes just not engage at cruise for a
while and then (with speed & TPS unchanged)
just decide to lock up. Looking at the scanner
this appears to be the PCM's doing, the TCC
Mode and the TCC action are in step but what
the tables command, is not always done.
So I'm scratching my head about what might
make the PCM decide to not do what I tell it,
at seemingly random times. Other than misfires,
which are logging zeroes in my case.
Presumably you'd see the flashing SES but maybe
not. Misfires might be affected by load (4th vs
3rd).
Now, I've been having a similar sounding problem
recently, the lockup will engage fine/normal
sometimes, but a couple of minutes down the
road it'll flare back to unlocked, then relock,
or sometimes just not engage at cruise for a
while and then (with speed & TPS unchanged)
just decide to lock up. Looking at the scanner
this appears to be the PCM's doing, the TCC
Mode and the TCC action are in step but what
the tables command, is not always done.
So I'm scratching my head about what might
make the PCM decide to not do what I tell it,
at seemingly random times. Other than misfires,
which are logging zeroes in my case.
After a top-end race with a Ferrari, during which I was forced to shift into 4th @ 6750 rpm, simply because I ran out of cam in 3rd, I started displaying HIGH TRANS TEMP warnings. Even though I took the car immediately to a trans shop and flushed the old fluid out, it was already too late, and I had to rebuild it. The 4th gear clutches were burned, AND the band was partially burned.
What was different about this time was that I went for quite a while, after the flush, thinking my TC lock-up was malfunctioning, because it would flare up in 4th gear only, going in and out of lock-up, but in 3rd NO perceptible slippage. After talking to the Vigilante folks, and being convinced their lock-up was fine because it was doing great in 3rd gear, I then took the car to a reputable tuner in my area, who was also perplexed, and spent quite some time with his HP Tuners trying to fix what he thought was a computer problem on lock-up programing...wrong. So, it fooled everyone, me, the reputable tuner, and even the tranny shop at first, until they opened it up, and could see the hard evidence.
Man I tried everything you could think of to keep from having to do the dreaded rebuild again, but finally gave in, and now it's just fine.
It was just so hard for me to believe it was the tranny, because it never slipped at the usual 3-4 shift...it was tight there, but after reaching overdrive, the thing would come out of *lock-up* at the slightest incline I would encounter on any given highway, and at any speed. Crazy, I tell ya!
Sooo, if you guys are having the same symptoms, better get to saving up for a rebuild. Good luck!
My problem is showing in 3rd and 4th, and I'm finding
hints that it's misfire related in the logs (although the
misfire counts are quiet, there's an "index level" that
moves in apparent sync). I have a new tune with all
the misfire tables set high, will see if that kills what I
can't quite catch.
You should be able to determine by logging whether
it is a transmission or a torque converter problem,
by looking at engine RPM, input shaft RPM and output
shaft RPM. If engine stretches away from input then
the converter is slipping; if input stretches away from
output then it's some internal friction that's slipping
in the trans.
hints that it's misfire related in the logs (although the
misfire counts are quiet, there's an "index level" that
moves in apparent sync). I have a new tune with all
the misfire tables set high, will see if that kills what I
can't quite catch.
You should be able to determine by logging whether
it is a transmission or a torque converter problem,
by looking at engine RPM, input shaft RPM and output
shaft RPM. If engine stretches away from input then
the converter is slipping; if input stretches away from
output then it's some internal friction that's slipping
in the trans.
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I had a similar issue last year. Just cruising in OD it would start to slip then grab. It slipped again so I put the car in D and was fine for a bit until it started slipping in D. I gave the transmission to a friend and he had the trans fixed. The input drum was cracked and the clutches were burned.
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On The Tree
Joined: Apr 2012
Posts: 113
Likes: 0
From: georgia
my car is doing the same thing, but it only started doing it after i wnet from 2.73s to 4.10s. so i founda good used 4l65e for 300$ so im going to go pick it up. i would build it but im going to rod run and im short on cash lol
