What did the north and south feel about slavery in the west?

It isn't right to generalize, because the North's populace did not all hate slavery, and the South's did not all support it. In your generalized terms, both the North and the South wished for the new states out west to have slavery laws in accordance with their positions. This almost led to war, but several compromises were made: The Missouri Comprimise, the Comprimise of 1850, and other deals, such as the Three Fifths Comprimise.

However, these only delayed war, and events such as Bleeding Kansas were instrumental in starting the Civil War