TCC lockup inoperable at higher speeds
01-14-2014, 08:55 AM
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Car: 87 Trans Am, 99 WS6, 16 Mustang GT
Engine: LB9, LS1
Transmission: 700R4, T56
Axle/Gears: 3.42 Posi, 4.10 Posi
TCC lockup inoperable at higher speeds
I took my car out yesterday for the first time since early December. Before I let it sit, the TCC lockup was working fine, but now it seems at around 50+mph the lockup does not engage. It also takes a while to shift into OD, and when it does, any variation in the gas pedal will drop it down into 3rd again. I suspect that's because the converter isn't locked. What might be the issue here? How can I diagnose it?
I had installed a Corvette servo right before I put it away, but everything still worked perfectly after. I don't know if that's part of the problem, but that might be useful info.
I had installed a Corvette servo right before I put it away, but everything still worked perfectly after. I don't know if that's part of the problem, but that might be useful info.
01-14-2014, 10:34 AM
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: TCC lockup inoperable at higher speeds
3 most likely causes: pedal switch, TPS or speedometer
Check your brake pedal switch.
Use a scanner to look at your TPS and Speed as the ECM sees it when it happens. See if the ECM is commanding lock up.
Check your brake pedal switch.
Use a scanner to look at your TPS and Speed as the ECM sees it when it happens. See if the ECM is commanding lock up.
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