Guys with tranny knowledge help me help my brother please!

[toupee]

Ok all, not really sure where I should post this exactly so it's going here.
My brother told me that his Chrysler Pacifica broke down on him and his family at the local grocery store. Here's what it did. 
He said he came out, started the.... thing (don't know exactly what you would call a pacifica... car... suv...van.....sut? lol)  Anyways, when he put it in gear and gave it gas he says it sounded like when you tie popcans to the back of your car and drive down the road.  According to him even when he puts it in park it will roll forward since it is parked on a grade.  He said the lever moves through all the gears freely and the sound is really only noticeable when he gives it gas.  It's an automatic (duh!) 
Any ideas on what the problem might be?

[GreenMachine]

My guess would be that the linkage came apart somewhere. However I'm not very knowledgeable with transmissions.

[375instroke]

Did he try to stop the car by putting it in park?  By the shifter moving freely, do you mean the shifter moves, but won't go into gear?

[Todd Wilson]

If its front wheel drive I wonder if it has something to do with the front wheel drive axle more then the transmission portion of the drive train.

Todd