Lost reverse, need help finding it. 727

Was the pump replaced when it was freshened up? May be the torque converter leaking down. I have a 06 Ram that sometimes won't move back in reverse until the pressure is pumped up. Also, had a 71 Charger that we had the trans rebuilt and the guy didn't replace the pump and it worked for all of 5 minutes before completely stop working.

Just a few thoughts. Good luck!