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Like the title says.... When people talk about their torque converters being locked up just exactly what in he11 do they mean? I'm under the assumption that when the truck is in gear and moving the TC is locked up but when others talk about this it would appear like they are locking it up and unlocking it at will while driving the vehicle. Is this possible?
In the higher gears, when you step down at highway speeds. Especially in 5th or 6th, you step down a little and it feels like the truck down shifts. While watching the scan gauge, the truck never shift to a lower gear.... torque convertor unlocked, RPM came up and truck speeds up. Then when the increase in speed is satisfied, it locks again and feels like it shifted.... locked.
When in locked condition, you get better mileage as its not slipping... in a round about way to say.
Watch the gauge, select gear. Count the shifts and confirm the numbers. When it feels like a shift and the number doesn't change.... it was a lock / unlock. I can feel mine 7 times, those extras coming in 5/6 gears..
Locked, unlocked.
If you step down hard, it will down shift a gear, unlock and allow RPM to come up. You want the converter locked for fuel mileage, why they want to lock it up fast with a tuning program, mileage suffers when slipping. Why you can really lug a manual transmission, it's directly connected thru the clutch... rpm come down on a hill and you have to shift to get rpm.... automatic transmission just unlocks the converter. .... rpm increases.
Thanks WatsonR, That sorta makes sense but it seems to me that the only time my TC is unlocked is when I'm traveling and pick my foot up a little and then reapply that I get the unlock-relock feel and raise in RPM for a second or two during that time. Thanks for the reply though, I understand a little better now what people are talking about. You did a fine job explaining it....I'm just mentally challenged
Thanks WatsonR, That sorta makes sense but it seems to me that the only time my TC is unlocked is when I'm traveling and pick my foot up a little and then reapply that I get the unlock-relock feel and raise in RPM for a second or two during that time. Thanks for the reply though, I understand a little better now what people are talking about. You did a fine job explaining it....I'm just mentally challenged
A torque converter in a automatic trans takes the place of a clutch in a manual. An oversimplified description is that inside the torq converter works like a fan (attached to the engine) blowing against another fan (attached to the trans) to make it turn. It of course uses fluid instead of air and clearances are very tight. This allows you to come to a stop and not stall the engine and under certain circumstances even multiply torque. Once in top gear and no longer speeding up it does "slip" a little. When it's in that situation, the PCM locks a clutch in the converter using a signal to a solenoid which mechanically forces the input and output "fans" to be mechanically locked together causing the speeds to be the same (no slip). While it is possible to interrupt signal with a switch it's not common to do that and no real benefit. Tuning (PCM software) can change the lock up point.
.... When people talk about their torque converters being locked up just exactly what in he11 do they mean? I'm under the assumption that when the truck is in gear and moving the TC is locked up but when others talk about this it would appear like they are locking it up and unlocking it at will while driving the vehicle. Is this possible?
