Nope, after returning everything to default, the fuel loading animation still does not occur with the PMDG 737-700. The fuel load occurs and GSX displays the progress, but the driver remains in the truck.
Perhaps GSX does not fully support the PMDG737 for the fuel (no animation). Also, I have orften noticed, that while the fuel is loading, the GSW can not be made to appear (even if I toggle the menu).