2007 S40 URGENT! Did engine swap...trans worked fine before,

[Craigd2599]

Hey fellas...
I bought a 2007 S40 2.4i with a bad motor. My mechanic is certified and has Volvo experience so this isn't shade tree. Replacement motor went in fine, they put it back together and everything was swell. Started right up, runs like a Swiss watch. They drove the car into the bay to begin with, so we know the trans worked fine. They never separated the torque converter from the trans during the install, so we know it is seated all the way on the input spline. Here's the problem...the car will not move. It engages, you can see that the spline is reading RPMS at the speed sensor but the car will not move. When you shift it into gear there is no RPM drop...it never comes under load. The trans worked fine beforehand. Did my mechanic miss something here?