Need help from the transmission gurus
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Joined: Oct 2008
Posts: 57
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Need help from the transmission gurus
I had the 700R4 in my 90 coupe rebuilt last week. They also replaced the torque converter. Since then, the lockup doesn't work right. It all works perfectly until the car gets fully warmed up, and then it won't go into lockup. I'm taking it into the transmission shop Monday morning. They ordered a new lockup solenoid for it but, talking to the guy I can tell he's puzzled about the temperature thing. He thinks it's either the solenoid or the throttle position sensor but I'm not so sure. I'm not confident the problem is electrical. What would cause a lockup torque converter to work flawlessly when the engine is cold and then quit working when it gets fully warmed up? Any ideas? BTW: When it is working properly the brake switch works right too. In other words, I can lightly press the brake pedal and it comes out of lockup and as soon as I take my foot off the brake it goes back it just like it's supposed to.
Race Director
Joined: Jun 2001
Posts: 10,956
Likes: 681
From: Marlboro country MA
I'd guess it may be either the solenoid or else the connection between the solenoid and the ECM, which controls it. Heat may cause just enough expansion to cause an open in the circuit.
