Newb ?, What is lock vs unlocked??
Thread Starter
12 Second Club
Joined: Jun 2005
Posts: 543
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From: Orlando, Fl
Newb ?, What is lock vs unlocked?? Sorry for this easy qiestion but, I hear people talking about it being locked or unlocked? Im assuming theyre referring to their converters. I dont know what it means to be locked or unlocked. Someone please correct my ignorance.
TECH Senior Member
Joined: Apr 2002
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From: So.Cal.
The torque converter ("TC") has a clutch inside it ("TCC");
the PCM can lock or unlock this clutch as it sees fit;
TCC unlocked: the TC multiplies torque and allows the engine RPM to drop less at the end of each shift (keeps engine in torque band); this improves vehicle acceleration.
TCC locked: the TC has no slip (and no torque multiplication) and transmits crank rotation directly into trans. input; this improves gas mileage and reduces heat generated by TC.
the PCM can lock or unlock this clutch as it sees fit;
TCC unlocked: the TC multiplies torque and allows the engine RPM to drop less at the end of each shift (keeps engine in torque band); this improves vehicle acceleration.
TCC locked: the TC has no slip (and no torque multiplication) and transmits crank rotation directly into trans. input; this improves gas mileage and reduces heat generated by TC.
