Jackscrew?? Not sure mine has one. I do know that mine has something like the old speedometer drive cable that goes from the motor to each side. It can come out of it's socket at either end, and the motor will run but the side that is loose does not move. If that is the problem, make sure the couch is even side to side, then with the foot rest out I can crawl under mine and re-insert the drive cable into the loose side. I have someone else tap the power button to ensure I have it fully inserted. When sure it is in place, I wrapped packing tape around the drive cable and a metal frame member to keep it in place. Both sides of mine have come loose in the past (one under warranty, and the dealer service ticket says they "reglued the drive chain"). Neither side has come loose since their tape jobs!
Paul (KE5LXU) ...was fulltimin', now parttimin'
'03 Winnebago UA 40e / '17 Jeep Grand Cherokee toad