510 D backhoe won't move.

My backhoe has always had good power and strong hydraulics with no noticeable lag in shifting. I got out to hook up a chain and got back in and it wouldn't move but wheels were free. (Park brake had quit working early this winter and I had to put a bigger fuse in or it blows fuse ) I might have 2 problems . Long story short with all tires in the air they rotate in reverse real slow in 1st and 2nd gear no matter what position FNR lever is in. Set it on the ground and driveshaft will spin in...

510 D backhoe won't move.

510 D backhoe won't move.