TCC slip after rebuild and new TC
06-16-2016, 11:36 PM
#1
TCC slip after rebuild and new TC A friend and I rebuild my 4l60e due to the infamous 3/4 clutch pack and used the street strip kit from Probuilt Automatics https://www.700r4l60e.com/store/prod...4&bestseller=Y which basically included all new bushings, seals, clutch packs, and a new stator. I also picked up a new 11" high performance TC from circleD. During the build everything went pretty smoothly, clearances were perfect, got the pump rebuilt and the new stator pressed in and lined up to the pin. Got it put back into the car and proceeded to start it up and break in the new clutches. Trans shifted great and all seemed fine, but then noticed it was not locking up in TCC. Actually thought that it was not locking up at all but eventually found out it is partially applying and so light than any amount of throttle more than light cruise will cause it to slip. Going up a slight hill for a prolonged period will produce a P1870 code. I have the TransGo ISO-CONV valve installed which basically disables PWM and causes TCC to lockup as soon as the TCC solenoid is commanded. I have tried different line boosters and TCC apply valves from Sonnax and transgo and all have the same result. Pretty much out of ideas here as we have been dealing with these issues for the last 3 months. I can go ahead and have circleD replace the TC under warranty but im still not 100% sure what the issue is.
My possible theory's
1. new TC clutch clearances not right (DOA TC)
2. low TC pressure leaking from valve body? (this issue was not present before the rebuild and transgo valve feels tight inside valvebody)
3. Stator not aligned properly (how possible is this if the guide pin aligned up fine.
I have a fitzall TCC valve that has seals for the PWM valve but I'm missing the inside valve because my buddy tossed it when the HD2 kit with the ISO-CONV valve said to discard it, but this kit should do the same thing as this valve.
Any help with this would be appreciated.
Thanks!
My possible theory's
1. new TC clutch clearances not right (DOA TC)
2. low TC pressure leaking from valve body? (this issue was not present before the rebuild and transgo valve feels tight inside valvebody)
3. Stator not aligned properly (how possible is this if the guide pin aligned up fine.
I have a fitzall TCC valve that has seals for the PWM valve but I'm missing the inside valve because my buddy tossed it when the HD2 kit with the ISO-CONV valve said to discard it, but this kit should do the same thing as this valve.
Any help with this would be appreciated.
Thanks!
06-17-2016, 09:34 AM
#2
We dont use the Transgo valve and I don't have the transgo instructions but I think you have to plug a hole in the plate when you remove the inner valve.
Other possibilities worn input shaft or bushings in stator. Torn or damaged lockup oring on input shaft. Torn or damaged Teflon ring on input shaft the top one . Restriction inside input shaft or pump and of course the seal in the converter apply piston itself damaged or piston damaged.
Other possibilities worn input shaft or bushings in stator. Torn or damaged lockup oring on input shaft. Torn or damaged Teflon ring on input shaft the top one . Restriction inside input shaft or pump and of course the seal in the converter apply piston itself damaged or piston damaged.
__________________
06-17-2016, 10:07 AM
#3
We dont use the Transgo valve and I don't have the transgo instructions but I think you have to plug a hole in the plate when you remove the inner valve.
Other possibilities worn input shaft or bushings in stator. Torn or damaged lockup oring on input shaft. Torn or damaged Teflon ring on input shaft the top one . Restriction inside input shaft or pump and of course the seal in the converter apply piston itself damaged or piston damaged.
Other possibilities worn input shaft or bushings in stator. Torn or damaged lockup oring on input shaft. Torn or damaged Teflon ring on input shaft the top one . Restriction inside input shaft or pump and of course the seal in the converter apply piston itself damaged or piston damaged.
New stator came with new bushings and input shaft looked good, though I didn't measure it, but I was not having this issue before the rebuild.
We did replace the O ring on the input shaft and it sits in there pretty deep so I would think its unlikely it could have been damaged on install of the converter but it is a possibility.
As far as restriction inside shaft or pump, is there anyway to test for that? I would assume a pump restriction would cause other low pressure issues as well.
06-17-2016, 01:58 PM
#4
Thanks for the reply! someone was nice enough to post the instructions to the HD2 kit https://ls1tech.com/forums/automatic...questions.html and it does not say to plug anything.
New stator came with new bushings and input shaft looked good, though I didn't measure it, but I was not having this issue before the rebuild.
We did replace the O ring on the input shaft and it sits in there pretty deep so I would think its unlikely it could have been damaged on install of the converter but it is a possibility.
As far as restriction inside shaft or pump, is there anyway to test for that? I would assume a pump restriction would cause other low pressure issues as well.
New stator came with new bushings and input shaft looked good, though I didn't measure it, but I was not having this issue before the rebuild.
We did replace the O ring on the input shaft and it sits in there pretty deep so I would think its unlikely it could have been damaged on install of the converter but it is a possibility.
As far as restriction inside shaft or pump, is there anyway to test for that? I would assume a pump restriction would cause other low pressure issues as well.
Like I said was not sure on the transgo Instructions. As for the oring anything possible we have in fact damaged one before installing trans on dyno so it is possible to do so a small nick is all it takes.
Feeds in pump can indeed be restricted without affecting line pressure but affecting lockup and lube, Not much way to check short of taking trans apart, You can check for good lube flow however by unhooking a cooler line and starting should be considerable,"
Not sure what else to tell you I suppose the apply feed in the plate could be to small or restricted but at this point I would probably pull trans send converter off and while its gone recheck everything lockup related,
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06-17-2016, 11:47 PM
#6
Like I said was not sure on the transgo Instructions. As for the oring anything possible we have in fact damaged one before installing trans on dyno so it is possible to do so a small nick is all it takes.
Feeds in pump can indeed be restricted without affecting line pressure but affecting lockup and lube, Not much way to check short of taking trans apart, You can check for good lube flow however by unhooking a cooler line and starting should be considerable,"
Not sure what else to tell you I suppose the apply feed in the plate could be to small or restricted but at this point I would probably pull trans send converter off and while its gone recheck everything lockup related,
Feeds in pump can indeed be restricted without affecting line pressure but affecting lockup and lube, Not much way to check short of taking trans apart, You can check for good lube flow however by unhooking a cooler line and starting should be considerable,"
Not sure what else to tell you I suppose the apply feed in the plate could be to small or restricted but at this point I would probably pull trans send converter off and while its gone recheck everything lockup related,
We're happy to take a look at the converter if you need us to. Times like this have me wondering why GM didn't do an ISS on the 4L60/65 transmissions.
As much as I would love to have you test it for me, If I'm going to pull the trans again I'd like to have a replacement... I don't have my own garage or driveway, doing in my buddies driveway and I can't leave the car there.
-Brian
As much as I would love to have you test it for me, If I'm going to pull the trans again I'd like to have a replacement... I don't have my own garage or driveway, doing in my buddies driveway and I can't leave the car there.
-Brian
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06-18-2016, 08:01 AM
#10
Moderator
As mentioned, a torn o-ring on the input shaft is a likely (most likely?) problem.
Can we assume it is a '99 or '02 trans?
In a long-ago thread, the rebuilt kit had the wrong year stator shaft; I don't recall the symptoms of that, but I suspect you would have no TCC at all.
If you want to switch to the Fitzall valve, perhaps Clinebarger or Performabuilt has a spare inner valve; I think I have already donated all mine to other members needing one for the same reason.
Can we assume it is a '99 or '02 trans?
In a long-ago thread, the rebuilt kit had the wrong year stator shaft; I don't recall the symptoms of that, but I suspect you would have no TCC at all.
If you want to switch to the Fitzall valve, perhaps Clinebarger or Performabuilt has a spare inner valve; I think I have already donated all mine to other members needing one for the same reason.
06-24-2016, 05:35 PM
#11
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There's a basic problem with the 4L60E control from
the PCM, as far as the converter clutch goes. That
is, 100% of nothing is nothing. TCC only gets a
variable (or in your case, all) of main line pressure
but GM decided to starve the line at low pedal and
idle (for CAFE I expect).
Some OSes, my tuning software has access to the
TCC-locked line adder. But before this came around
I just bumped down the force motor milliamps to get
it so I had more line pressure when the PCM commands
"0%" (which is not zero PSI, but as low as it can go).
Logging commanded pressure when I had my own slip
issues, I saw the 0% well into cruise and light-grade
pedal position. Meaning my converter would groan
and hoot on every cloverleaf, etc.
the PCM, as far as the converter clutch goes. That
is, 100% of nothing is nothing. TCC only gets a
variable (or in your case, all) of main line pressure
but GM decided to starve the line at low pedal and
idle (for CAFE I expect).
Some OSes, my tuning software has access to the
TCC-locked line adder. But before this came around
I just bumped down the force motor milliamps to get
it so I had more line pressure when the PCM commands
"0%" (which is not zero PSI, but as low as it can go).
Logging commanded pressure when I had my own slip
issues, I saw the 0% well into cruise and light-grade
pedal position. Meaning my converter would groan
and hoot on every cloverleaf, etc.
06-24-2016, 10:57 PM
#12
Kinda big update, sorry I have not updated before but I did install a remanufactured valve body with the sonnax TCC Regulator & Isolator Valve Kit and after that car was still having the same exact issue, so I did hit up CircleD and they are sending me a new converter. BUT! Just today I decided to try the check ball in TCC valve test (which I was a little sketched out about doing as there really wasn't much info on the exact procedure) and after firing it up and then putting into gear it would lock up and stall the engine quite fast. Just to try to rule out that it was not just the light locking up like before I tried the test again but this time revved up to about 1500 rpms and then put it in gear and it stopped just as fast. So now I feel like I'm at a complete loss and I'm thinking there is a blockage between the PWM converter isolator valve and the TCC valve? That's my best guess but I would have no way to test or even know what I am looking for. I am assuming that since I got the new valve body with the sonnax TCC fix and the pass of the check ball in TCC valve solenoid test the converter is good, the valve body is good, the input shaft is good, the tcc valve is good. Not sure where to go now, and that I should just do what I should have done in the first place and pickup a 4l80e and throw it in.
I understand mostly what your saying but I'm not quite sure what you are asking/recommending me to do... I do have HP tuners and have only messed with the TCC duty cycle though I have copied over the shift pressures and setting over from my diablo sport tuner which would be the only other modified settings other than the TCC apply which I set to 90-100% duty cycle whenever applied.
There's a basic problem with the 4L60E control from
the PCM, as far as the converter clutch goes. That
is, 100% of nothing is nothing. TCC only gets a
variable (or in your case, all) of main line pressure
but GM decided to starve the line at low pedal and
idle (for CAFE I expect).
Some OSes, my tuning software has access to the
TCC-locked line adder. But before this came around
I just bumped down the force motor milliamps to get
it so I had more line pressure when the PCM commands
"0%" (which is not zero PSI, but as low as it can go).
Logging commanded pressure when I had my own slip
issues, I saw the 0% well into cruise and light-grade
pedal position. Meaning my converter would groan
and hoot on every cloverleaf, etc.
the PCM, as far as the converter clutch goes. That
is, 100% of nothing is nothing. TCC only gets a
variable (or in your case, all) of main line pressure
but GM decided to starve the line at low pedal and
idle (for CAFE I expect).
Some OSes, my tuning software has access to the
TCC-locked line adder. But before this came around
I just bumped down the force motor milliamps to get
it so I had more line pressure when the PCM commands
"0%" (which is not zero PSI, but as low as it can go).
Logging commanded pressure when I had my own slip
issues, I saw the 0% well into cruise and light-grade
pedal position. Meaning my converter would groan
and hoot on every cloverleaf, etc.
06-25-2016, 09:13 AM
#13
Moderator
Jim is saying that the line pressure in a 4L60E is quite low at low throttle positions. The spec is as low as 55psi at idle and it might not be much higher at cruising.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
06-25-2016, 09:59 AM
#14
TECH Junkie
Jim is saying that the line pressure in a 4L60E is quite low at low throttle positions. The spec is as low as 55psi at idle and it might not be much higher at cruising.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
https://ls1tech.com/forums/automatic...nts-4l60e.html
06-25-2016, 11:46 AM
#15
Jim is saying that the line pressure in a 4L60E is quite low at low throttle positions. The spec is as low as 55psi at idle and it might not be much higher at cruising.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
Since higher line pressure takes a bit more engine HP, he is postulating that GM accepted the low line pressure for a tiny increase in MPG.
Installing the TG or Sonnax boost valve will increase the base line pressure to about 75 psi, which might then help with the TCC lockup.
Cpt.Derrek: Could you please provide a link/info about the "check ball in TCC valve test"; I am not aware of it and it might be useful to others. Thanks.
I think this is what he is talking about. Post #17 & 18.
https://ls1tech.com/forums/automatic...nts-4l60e.html
https://ls1tech.com/forums/automatic...nts-4l60e.html
08-18-2016, 03:58 PM
#18
Well thought I'd update you all. We pulled out my TCC problematic 4l60e and dropped my rebuilt 4l80e in and we still need to finish a few things like sharing the rear VSS sensor with controller, low profile return cooler line, and longer yoke, but all is working other than those. Anyways pulled the converter off the 4l60e and the input shaft seal was totally torn.... Anyways so obviously that was causing my TCC issues and I guess there was enough pressure to lightly apply TCC.... so now I'm stuck with a perfectly good built 4l60e with no where to store it. Anyone want a built 4l60e? just needs a new input shaft seal lol.
08-18-2016, 04:36 PM
#19
Moderator
Cool, but how much is a new input shaft seal? 
I assume you are referring to the o-ring.
While I listed that as the likely problem, I know that checking it required removing the trans.
A 4L80E is a nice upgrade that should serve you for many years!
I assume you are referring to the o-ring.
While I listed that as the likely problem, I know that checking it required removing the trans.
A 4L80E is a nice upgrade that should serve you for many years!
08-18-2016, 05:00 PM
#20
I guess I should have listened to you lol. The guy I bought the kit from said it was very unlikely and the fact that it was still partially locking up and seemed to completely lockup when I tried the check ball test... I guess I'm glad I can at least sell the trans as a working unit and I know what the issue was. Thanks for your help mrvedit!
And yeah I hope so, and I like the fact that 1st gear is not as steep since dropping into 1st was difficult in autocross and road courses. Also can't wait to get paddle shifters! WOO