The other night I started my dodge diesel 2500 and backed out of shed then drove it slowly to other side of my shed. When I got back in it it would not move when I put it in drive, 2nd or 1 (low). It will back up but is not acting normal in reverse. It is a automatic transmission and have never had an issue with it. Any ideas what this problem could be or what can be analyzed? Repair shop I pulled to thinks tranny bad but they have not pulled the pan on the transmission to check