When does a torque converter lock the transmission?
When does a torque converter lock the transmission?
The torque converter locks when the engine rpm (impeller/housing speed of converter) and the transmission input shaft (turbine speed of converter) are roughly equal — thereby improving efficiency for cruising, but also mitigating any torque multiplaction effect of the torque converter.
What happens when you uncouple the torque converter?
Any input from the accelerator decouples the TC friction clutch, and the transmission reverts to a fluid drive scenario with torque multiplication. This also occurs while shifting (if any), as such a shift would be very harsh wihout the fluid damping effect of the TC. So in most vehicles, a downshift to 3rd would uncouple the TC clutch.
Can a Over Drive Cancel lock in 3rd gear?
The over drive cancel will make 3rd the highest gear and then it can lock in 3rd on most transmissions. More modern 6 speed transmissions keep the torque converter locked even when shifting.
How does the torque converter work on a 90s car?
Lifting the throttle usually commands the transmission into the highest gear (for fuel efficiency) unless your TCM has a “sport” mode or some such that holds it in gear longer. The torque converter lock on a typical 90s 4 speed automatic won’t engage unless the transmission is in the highest gear, and the throttle position is fairly low.
Is there a way to unlock the torque converter?
Unlocking the torque converter is achieved by disconnection of the +12 volts, or the transmission downshifts out of 4th gear. We also include a cruise control style brake switch that works perfectly to disconnect the +12 volt power to the lock up module when the brakes are applied.
Why does my torque converter lock up when I Go overdrive?
If you’re unfamiliar with exactly what the torque converter lock up is or does, the easy answer is, the lock up clutch takes stress off the fluid coupling of the torque converter and it helps decrease the amount of heat being generated at higher cruising speeds. Converter lock up wasn’t really an issue until the overdrive came about.
What causes the torque convertor clutch to disengage?
There is a solenoid in your GM converter that causes the the torque convertor clutch (TCC) to engage and disengage. When the TCC solenoid receives a signal from the engine control module (ECM), it opens a passage in the valve body and hydraulic fluid applies the TCC.
What should I do if my converter lock up?
If the TCC fails to disengage when the vehicle comes to a stop, the engine will stall. Before attempting to diagnose converter clutch electrical problems, mechanical checks such as linkage adjustments and oil level should be performed and corrected as needed.
