TCC unlocking at coasting / Highway Speed

It's my wife's 2006 TBSS AWD. Problem has plagued us for years, basically the tranny acts just fine thru the gears lock up etc. Hit the freeway locks up fine and so on.

Problem arises when you lift to let a car merge in front of you or try to just coast. The converter IMMEDIATELY unlocks even if you are still doing 70-75 MPH. It's annoying as hell and I suspect might have taken out a converter bearing once before (from the constant locking and unlocking).

Any help on this? I've done lots of research and just hoping for a clue.

Thanks.

Your truck is fine, they all do this. I think the there are tables to fix this now.

Yes I just downloaded 2.24 and I'm thinking I should disable "Min TPS" in the Minimum throttle release section of Auto TCC tab? Can anyone confirm this?

Either that or zero out the "Min TPS" table?

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Originally Posted by 99socalfrc

Yes I just downloaded 2.24 and I'm thinking I should disable "Min TPS" in the Minimum throttle release section of Auto TCC tab? Can anyone confirm this?

Either that or zero out the "Min TPS" table?

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Check that upon reviewing the tables it looks like the trick is to reset the hi vs. lo speed threshold from the factory setting. Looks like right out of the box it is set to run in low speed mode all the time. Causing TCC to unlock anytime TPS% is below 7%.

When I was ready to start playing with this, I was going to see what an LS2 GTO file looked like.

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Originally Posted by snowvette

When I was ready to start playing with this, I was going to see what an LS2 GTO file looked like.

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Went back and checked my 05 GTO tune. The entire section is disabled from the factory.

1st question is it actually unlocking, have you a logfile showing TPS % vs TCC status?
make sure its an actual unlock and not a slip, i had the EXACT same problem you had, could not cruise under 5% tps because the tcc would "unlock" and it drove me bat **** crazy. Turned out to be the force motor not applying enough pressure to the TCC clutch to keep it locked up. please Log until this happens and make sure the PCM is actually commanding unlock. make sure to add the PID on the text readout for TCC Slip RPM also. just make sure you pull over just after it happens and stop logging, save the file then review it...you thought driving with a Cell phone stuck to your face was bad....

Quote:

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Originally Posted by 99socalfrc

Check that upon reviewing the tables it looks like the trick is to reset the hi vs. lo speed threshold from the factory setting. Looks like right out of the box it is set to run in low speed mode all the time. Causing TCC to unlock anytime TPS% is below 7%.

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minimum throttle release i think is only a fail safe parameter
but this is what mine looks like.
low speed VSS=256
high speed VSS=256
low speed tps low=0%
low speed tps high=0%
high speed tps low=0%
high speed tps high=0%


my apply/release shows
256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0
256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0 256.0
35.0 35.0 35.0 35.0 50.0 50.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 256.0 256.0 256.0 256.0
255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0
255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0 255.0
28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 255.0 255.0 255.0

duty cycle is 99 min and 100 max

my resolution to this exact problem happened to be none of the above.
read this....
http://www.hptuners.com/forum/showth...ip-Elimination!!!!

Wow, I'm glad my solution fixed your problem. just keep an eye on the trans temps and make sure to log tcc slip RPM just to make sure your 1:1 during lockup. My problem came back but it turned out the tune was only a Band-Aid to the problem, now my TCC is randomly going 1:1 and most of the time just slips like a slush box. In my case the sensitivity for the pressure control module was not strong enough to throw the CEL for it. Turns out my BRAND NEW B&M transmission is at fault, waiting on B&M to tell me they will warranty the converter and the trans because I have had issues from day 1, first converter was out of balance so it was shaking the car violently, but its demise was the out of balance issue burned out the clutch and caused excessive heat build up so I had to return that, I asked them specifically to cut it open and tell me what failed and why; they responded with "yep its bad". Had they done what I asked in the first place I wouldn't have to pull the trans for the 3rd time and if you've ever pulled the trans on an LS1 F-body you know how much of a hassle this is.

Now during lockup I randomly get sol-lock (force motor 0% duty cycle and Line pressure 38%) which means the valve body is toast or tcc sol is toast or even the tcc valve itself) but I know for sure the second hole-shot 2400 is now fried too. B&M has been there with me every step of the way but unfortunately it seems I know more about their LS1 trans than they do, which scares the S out of me. I asked if the converter has an OE style lockup clutch they say YES, then I ask "ok, what is the min/max slippage allowed" they said lockup=1:1 or .9% slip and unlocked =idle +800 or 15% slip which puts me to the correct stall speed, but guess what it sometimes is 1:1 and sometimes 10-300rpm of slip during lock. Tried upping the force motor another 10% and -15 shift pressure for 1>2 shift and it still gives me whiplash which normally I would be like HELLS YA! but having a whiplash 1>2 shift in stop n go traffic gets rather cumbersome. But at that line pressure I thought I had it pinned down, was perfect all the way to work then of course on the way home guess what.... yep full stall speed @ lockup, no resistance from the TCC. Hopefully at some point HPtuners will add a parameter where you can up the TCC pressure separately instead of going balls deep in the force motor and getting chirp in 2>3 shift and neck breaking 1>2.:doh:

Any updates ?

I just installed a circle D 3200 converter and its doing the same thing, locks and unlocks a lot during cruise. I dropped the tcc release speed 2-3mph across the board .
It definitely helped, its sort of a band aid fix though and now im second guessing if this is ok for the converter . Any opinions ?

Also what do you other TBSS guys run for TCC duty cycle min ?
I left mine stock for now , would it help to set it at 90 and which is better for the converter ?

If your tcc unlocks when you let off the throttle and locks back up a couple seconds later when you get back on the gas, that's normal.
If it unlocks for extended periods of time before locking again, you need to adjust your misfire table a little.
http://www.tbssowners.com/forums/sho...hlight=misfire

Ya I guess its normal . Is dropping the unlock mph like I did ok still ? I like the way it stays locked I just dont want to damage the trans or converter .

I'll try to edit the misfire table , should I set the code P0300 to No Reporting or edit the actual table ?

I only edited the table.

K , is dropping the stall release speed a few mph ok ? I do like how it holds much a longer when cruising

It should be ok. And I believe my duty cycle is 90 min and 100 max. I've gone higher on the min but the lock up is pretty harsh.

To get rid of throttle tip in tcc unlock while at cruise put min release table hi and low tps for hi speed threshold both to 0 percent. This will keep the tcc from unlocking and relocking when take your foot off the gas and quickly put your foot back in it.

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Originally Posted by gmaceachern0425

To get rid of throttle tip in tcc unlock while at cruise put min release table hi and low tps release for hi speed threshold both to 0 percent. This will keep the tcc from unlocking and relocking when take your foot off the gas and quickly put your foot back in it.

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