Torque converter lock up

[Bichselmnop]

Went to drive my car to school the other day and noticed while I was going around 60mph that my rpms where around 2000 instead of the usual 1600. After about 10 minutes of driving my rpms fell to 1600 and I didn't have a problem anymore that day, but did it the very next day the exact same way. It seems that now that the weather has gotten cold here (around 30ish in the morning) my torque converter doesn't lock up unless I've been driving for a while. Is this normal for this weather or is my converter taking a crap?

[Bichselmnop]

Just drove it and it seems to kick in when the car is around 150 or 160.

[Archon]

It sounds pretty normal. When it gets colder around here, even with engine temps up, it takes longer for the lockup to occur. Below about 15*, it can take a good 10-15 minutes of highway driving for it to lockup.

[Mark Fahey]

Don't forget that this design converter isn't just on or off but will also partially engage as the engine warms up.