I'll be watching this I have the same problem.
On my 2011 Ford I had to buy a new puck like they used on the roof because both the GPS and Sirius antenna were in the one puck. So when I tried the magnetic one on the hood I had great Sirius reception but no GPS.
I'm not sure on the Dodge if the magnetic one well work if you have the GPS. Also I don't know where the SXM box is located on the Ram. The Ford it was on the driver side, and it appears on the GM it is behind the glove box. I hope someone knows.
It must be nice to live where you can work on your truck at this time of year. Right now it is 33* with a wind chill of 17.5*