Convertor not locking up
Thread Starter
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Convertor not locking up
Hi,
When my 93 (126k miles, 2.73 rear) gets warmed up - drive for about 20 minutes - the convertor won't lock up at the appropriate speeds (over 45mph or so) and constant throttle. Before being warmed-up, it locks up, but as it gets warmer the lock-up process goes away. It tries for a few times and locks and unlocks then after that it doesn't try that I can see or feel. Next morning, same actions as it warms up.
Trans doesn't slip, shifts great, just runs at 2000rpm at 70 instead of 17-1800.
Had fluid flushed (about 11 qts not just 4) with no change in lockup action.
Haven't driven with a Tech hooked up, so that is probably the next step.
Any other ideas?
Thanks,
walt z.
When my 93 (126k miles, 2.73 rear) gets warmed up - drive for about 20 minutes - the convertor won't lock up at the appropriate speeds (over 45mph or so) and constant throttle. Before being warmed-up, it locks up, but as it gets warmer the lock-up process goes away. It tries for a few times and locks and unlocks then after that it doesn't try that I can see or feel. Next morning, same actions as it warms up.
Trans doesn't slip, shifts great, just runs at 2000rpm at 70 instead of 17-1800.
Had fluid flushed (about 11 qts not just 4) with no change in lockup action.
Haven't driven with a Tech hooked up, so that is probably the next step.
Any other ideas?
Thanks,
walt z.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You can monitor TCC lockup by connecting a test light between ALDL terminals F and A (that's for my '86 -- it might be different for your year). The light will light when the TCC is NOT locked. That signal comes from the ECM so that doesn't mean the torque converter is actually locking.
On my car the only conditions for TCC lockup are that the coolant temperature must be above 122° and the speed must be above 40 MPH.
On my car the only conditions for TCC lockup are that the coolant temperature must be above 122° and the speed must be above 40 MPH.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Be sure to check connector going into side of transmission - terminals and connector in good condition and firmly seated. TCC uses a 2nd gear switch and TCC solenoid both are found by removing pan. 2nd gear switch keeps TCC from engaging in 1st gear. ECM can engage TCC in 2nd for fuel economy. TCC solenoids do have a habit of failing hot, either allowing TCC to stay on - normally causing near stall or flare during 1-2 or 2-1 shift. Or off - no TCC; which may not set DTC since electrically ECM sees it working. Typically switch and solenoid are replaced at same time. Good luck.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Be sure to check connector going into side of transmission - terminals and connector in good condition and firmly seated. TCC uses a 2nd gear switch and TCC solenoid both are found by removing pan. 2nd gear switch keeps TCC from engaging in 1st gear. ECM can engage TCC in 2nd for fuel economy. TCC solenoids do have a habit of failing hot, either allowing TCC to stay on - normally causing near stall or flare during 1-2 or 2-1 shift. Or off - no TCC; which may not set DTC since electrically ECM sees it working. Typically switch and solenoid are replaced at same time. Good luck.
My ECM will lock the converter in any gear, including 1st. The switch in the trans is for OD so the ECM knows that the trans is in OD. It is used to keep the UPSHIFT light off.
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
The only thing the factory put in an 86 is an over temp device in the pan that will lock it up.
I've never heard of an automatic transmission controlling an upshift light.
In my opinion you have some issues with your trans/wiring/something.
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
Hi,
When my 93 (126k miles, 2.73 rear) gets warmed up - drive for about 20 minutes - the convertor won't lock up at the appropriate speeds (over 45mph or so) and constant throttle. Before being warmed-up, it locks up, but as it gets warmer the lock-up process goes away. Any other ideas?
Thanks,
walt z.
When my 93 (126k miles, 2.73 rear) gets warmed up - drive for about 20 minutes - the convertor won't lock up at the appropriate speeds (over 45mph or so) and constant throttle. Before being warmed-up, it locks up, but as it gets warmer the lock-up process goes away. Any other ideas?
Thanks,
walt z.
Any scanning device will tell you the tcc solenoid is getting power while the tcc is unlocked.
The snout is plastic, it reacts very well to temperature.
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Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The UPSHIFT light is controlled by the ECM. It will turn on the light if you go faster than 40 MPH and the trans is not in OD. There is some delay between the time you go over 40 MPH and the light comes on, about a minute or so. I assume that's to keep the light from flashing if you're going right around 40 MPH and your speed is varying slightly.