I have a 2000 SS and have a few issues that I assume may be common. Looking for some insight:

Issue #1:
There is a problem with the trans mount, causing the trans to move when shifting. However the trans also seems to be missing the proper shift points. When you step on the gas (normal, not to the floor) it waits a second before shifting and then seems to upshift to a higher gear than it should. It's very inconsistant when shifting and is causing an issue when trying to put the power to the pavement.
Can someone tell me what the problem is and if it's in anyway related to the failed mount?

Issue #2:
There is a noise coming from the rear (can't tell if it's near the wheel or differential). Not sure how to describe it in writing but it's like an uneven pulsing sound reletive to the wheel speed. I've heard that there is a common problem with the differentials, but not sure what exactly it is.
With this very poor description, can someone let me know if they know what the issue is?

Any help in determining what these issues are would be appreciated.

Thanks!

There is no possible way anyone here can diagnose your problem with out any hands on test. You need to take your car to a reputable transmission shop.