how do i know how much fluid is in the trans

If you want to know how much there should be- consult the capacities section of your owner's manual. If you want to know what the level is- pull the trans dipstick under the hood. I think that it is orange on newer GM cars, and has a gear cog symbol on it.

There is no dipsitck on this car. If you look on the top of the transmission, you will see a large red cap. This is where fluid is added. You check the fluid level by removing a plug on the side of the transmission.