torque converter lockup????

i've heard of it... and have been told that a wire on the aldl can make this happen....
if you'd like to please explain this to me, i'd appreciate it
thanks

 

I think that's on the electronicly controlled transmissions that are around 1991 and newer.

 

Tas, you should delete your post. It shows that you know zip about trannys.
The lockup tcc is in all thirdgens (with the th700r4 or 4L60). The lockup is for better gas milage. It basically stops the torque converter from slipping as much as it would without it being locked. For some cars you'll go faster if you have a switch to just have the tcc locked. The problem is when you come to a stop it'll bog because the tcc is still locked. You have to remember to switch it on and off and it isn't always a good thing. If you've got the time, do the switch and see if you can feel a difference. There are so many parameters that control when the tcc should be unlocked that it's hard to tell if the switch is working.
If you give it a half throttle (hard) acceloration and flip the switch you should feel it but this can make your car slower, not always faster. The tcc slips a little to keep your tranny higher in it's power band. It's like a stick and slipping the clutch a little. If you do it right it can be faster, if you don't and pop the clutch too soon it'll bog. It's a tuff call but I wouldn't bother with it. It'll lock when you need it and unless you've got some wicked rear gears like 3.73 or higher you'll probably just make the car slower.
It'll let it go on that note.

 

Here goes...

Between the engine and the transmission is the torque converter. This device consists of two sets of what look like fan blades, one inside the other. (A donut hole inside a donut. hehe) One fan's connected to the engine, while the other is connected to the tranny. (They're not really fans, I just don't know the proper term.)

Anyways, these are surrounded by liquid. When the engine turns it's fan, it gets the liquid churning, and the tranny fan starts spinning (which thus transfers power to the wheels.) Since it's a fluid connecting the engine and the transmission, the engine has to spin a certain speed before the wheels will start turning. (This is how automatics idle in drive at a stoplight without stalling.) The stall speed requires to the maximum RPM that the engine can turn with the wheels not moving. (I.E., if the stall speed is 2200RPM, then your engine won't rev any higher than 2200RPM if you're holding the wheels still.) The brakes on your car won't hold the rear wheels still to ever see the stall speed, but things like transmission brakes will. ANYways... heh

Because the engine and the transmission are not directly connected, there's some slipping. This is useful when you're at a stoplight, but detrimental to gas mileage at higher speeds, such as highway driving, because some of the engine's power is being lost in the torque converer. So, they added (basically) clutch plates to the transmission that, when the torque converter locks up, touch eachother, allowing for a direct connection between the engine and the transmission, and the power's transferred more completely.

I know that was pretty long winded for a short answer, but.. *shrug*. heh

 

wow,
you explained that very well, that is actually the best explanation i've ever gotten of a torque converter too
thank you so much....
you've been very helpful...
thanks

 

http://www.howstuffworks.com/automatic-transmission.htm/printable