TCC Lockup is Intermittant.... why?
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Le Mans Master
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From: Fort Worth Texas
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TCC Lockup is Intermittant.... why?
When the car is cold the TCC will lock up and feels fine. When the car is warmed up, it will disengage while cruising, then if I slightly press the gas pedal, it will slip back into lock, but upon releasing the gas to a steady cruise again, the TCC will unlock.
is the solenoid going out or the TC itself?
is the solenoid going out or the TC itself?
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From: Eagle IDAHO
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Re: TCC Lockup is Intermittant.... why? (Marcho Polo)
Yo Craig,
This has come up at least ten times on the Forum in the last couple of years.
Mine does exactly the same thing. I have been working on this for almost a year. Seems that the ECU uses the TPS voltages to determine part of the lockup/unlock algorithm. So at zero throttle the TC is unlocked and it locks at some point when the throttle is tipped. From all I can find out, this is considered normal. If you have a "loose" TC, the effect is more annoying.
My work-around is probably going to be a Illuminated push button on the console wired to a relay so that I can manually lock the TC when the speed is over say 45. I haven't drawn the schematic yet, but I am pretty sure that it can be set up that the car will unlock it at brake application, and when the trans is in any other gear than OD (4).
Using the relay I can set it up for press to lock and press to unlock. Here is a link to an interesting way to use the unused cartoon panel on my 85 for an indicator: (Thanks to Jonas Bylund the creative Swede)
http://w1.601.telia.com/~u60113744/o...d/over_eng.htm
Did you ever get a chance to look up my chip mods?
Best wishes, Tom
PS it is below zero here with snow up the wazoo.
[Modified by NHVett, 8:37 AM 1/15/2003]
[Modified by NHVett, 8:40 AM 1/15/2003]
[Modified by NHVett, 8:42 AM 1/15/2003]
This has come up at least ten times on the Forum in the last couple of years.
Mine does exactly the same thing. I have been working on this for almost a year. Seems that the ECU uses the TPS voltages to determine part of the lockup/unlock algorithm. So at zero throttle the TC is unlocked and it locks at some point when the throttle is tipped. From all I can find out, this is considered normal. If you have a "loose" TC, the effect is more annoying.
My work-around is probably going to be a Illuminated push button on the console wired to a relay so that I can manually lock the TC when the speed is over say 45. I haven't drawn the schematic yet, but I am pretty sure that it can be set up that the car will unlock it at brake application, and when the trans is in any other gear than OD (4).
Using the relay I can set it up for press to lock and press to unlock. Here is a link to an interesting way to use the unused cartoon panel on my 85 for an indicator: (Thanks to Jonas Bylund the creative Swede)
http://w1.601.telia.com/~u60113744/o...d/over_eng.htm
Did you ever get a chance to look up my chip mods?
Best wishes, Tom
PS it is below zero here with snow up the wazoo.
[Modified by NHVett, 8:37 AM 1/15/2003]
[Modified by NHVett, 8:40 AM 1/15/2003]
[Modified by NHVett, 8:42 AM 1/15/2003]
Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 9,663
Likes: 1,682
From: Fort Worth Texas
2024 Corvette of the Year Finalist - Unmodified
2023 C8 of the Year Winner - Unmodified
2020 Corvette of the Year Finalist (stock)
2019 C7 of Year Winner (stock)
Former Moderator
Cruise-In I-II-III Veteran
Re: TCC Lockup is Intermittant.... why? (NHVett)
yup, I remember people having similar conditions. Strange thing though, when I try to force lockup by grounding the TCC solenoid in the ALDL, it still won't lock. That tells me it's not a computer/TPS problem, but a failure with the TCC solenoid or the TC. :(
that link is way cool! I had noticed those lights on my '85 too. That's a pretty neat idea.
that link is way cool! I had noticed those lights on my '85 too. That's a pretty neat idea.
Safety Car
Joined: Dec 1999
Posts: 4,691
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From: Framingham MA
Re: TCC Lockup is Intermittant.... why? (Marcho Polo)
To me that sounds more like the soleniod, as I would think that if the clutch in the TC was going it would chatter, but I am only speculating (My co worker TC clutch started to go and it chattered.) I would drop the tranny pan and apply power/gnd to the solenoid and see if it does something.
BTW Didn't you have a some TCC wiring issue in the tranny with your 85?
[Modified by dgoodhue, 1:37 PM 1/15/2003]
BTW Didn't you have a some TCC wiring issue in the tranny with your 85?
[Modified by dgoodhue, 1:37 PM 1/15/2003]
