i just purchased a 05 SRT6 and when you start off there is a noise like something is hitting the floor board it's gets louder but at about 45. Mph it goes zaway. If you hit the accelerator passing a car it does it ago but gradually stops. I ordered a transmission mount to see if that is the issue. Today I barely pulled out and you can hear this click click clicking sound so that tells me it's in the transmission or driveshaft. Any suggestions. It has 197k miles.

You must get under the car and see what it is by checking what is loose. Some thread problems are replied to by multiple people offering multiple interpretations of the fault which could make you replace multiple items. This gets expensive and may or may not solve the problem. Basically that is the way some dealers solve problems they do not understand, they use a shotgun approach to a problem solvable by one well placed bullet.
On eBay you find good and bad items, you just have to sort the wheat from the chaff. Make sure you buy quality items as you do not want to do the job twice. Do not buy parts using the Chrysler part number, most parts have a Mercedes part number which are much cheaper 99% of the time. Chrysler dealers get the parts from a Mercedes dealer add a Chrysler label with their part number on it and a large increase in the price of the item.