Transmission will not pull after about 5 minutes or until it get hot.

What is your question?

My car sounds like the transmission pump is wining and when you start it the car will pull for just a few minutes. Then the wining stops and the car will not pull or reverse.

What makes this problem better or worse?

It is worse once the car is hot.

How long has your 2009 Buick LaCrosse had this problem?

A few days.