What is lock-up with regard to torque converters? Why and when does it happen? For example, does it only happen when you accelerate hard from a stop or while driving or both? When this lock-up occurs does it effect the shifting to the next gear? Please help as I have absolutely no clue about this. After searching I could not gather the answers I was looking for. Thanks again for the help!

-Nick

 

Try this
http://auto.howstuffworks.com/torque-converter2.htm

 

OK, I know how it works...now in "Torque Converter for Dummies" terms please. Thanks! I want to know if it is normal at a certain RPM or speed that the car might tend to hold a gear a little longer without shifting should you stay at that constant speed.

 

Anyone with a PI TC can add some insight as to how the car shifts before and after...please help!

 

The PI torque converter does 2 things.

1. Multiplies torque at lower rpms which in turn you will notice the car down shifts much more readily with less throttle dip in. You easily adjust to this for daily driving.

2. It gives the car a higher stall speed (when the engine speed is matched to the transmission speed). Below the stall speed the torque converter and engine are spinning faster than the transmission (this is similar to slipping a clutch in a manual car) This gives you additional off the line acceleration at lower rpm which makes a significant difference in the way the car reacts to throttle input from a stop.

Both these things are immediately noticeable but very easy to live with. The car is still easily driven during normal daily driving. You will notice a 1~2 mpg decrease during stop and go driving just because the car is much more willing to rev. This all depends on driving habits.