How can you tell if torque converter needs replacing?

we had a 2004 Ford an the torque converter was bad and what it did was not shift down in geers it would go strait from drive down to first so we repleace the converter and now it works find.

4.24.11

For further explanation and more symptoms of how to tell if a torque converter is bad follow this link on Ehow.com: http://www.ehow.com/how_5197449_tell-torque-converter-bad.html