Tom, it would be helpful to narrow that a bit.. Try to pinpoint and discribe the rattle location.. does it change when ya jiggle the transmission lever without putting it in gear, does it completely go away when it is in forward or reverse or both.. Is it coming from the packing box area..All the belts tight? Air cleaner hitting something? loose motor mount? Hours on engine? Transmission oil level OK?
The forum guys and girls will gladly pitch in .. but we need a few more hints !!
Welcome aboard !