1997 Other Saturn Models Rattle when at idle

I have a 97 Saturn SL1 w/1.9L engine and automatic transmission. When I stop for any reason while the car is still in gear, I hear a rattling noise which seems to be coming from under the center console area. This problem originally only occured when in gear and at a stop but has more recently began occuring even when the car is not in gear. I looked under the car at the exhaust system and I don't seee any parts loose. There is a heat sheild that runs down the center of the car and begins right under the center console area. Therefore, I am wondering if that could be the culprit. If I accelerate or up the RPM's even the slightest, the rattling will quit. However, the transmission has also been shifting very hard when I change gears. The transmission operates fine while driving, but if I shift from reverse to drive, you can sometimes hear a loud clunk or thump sound as if the transmission just fell out the bottom of the car. I wanted to take a look at the tranmission mounts, but I'm not sure what signs to look for. There is an anchor mount on the bottom rear but thus far I am not even sure how to get it out. There also appears to be another mount on the front side, which seems to anchor the transmission in a manner to keep it from twisting. I would like to get more input on this problem. Is there any way to check the transmission mounts before actually taking them out and just replacing them and what else can I check for that may likely be causing the noise? Thanks for the help!