Window Motor Trouble

1991 Acura Legend LS The other day I rolled down my passenger window a couple of inches and then wasn't able to put it back up using either switch. I removed the passenger door panel and tested the switch and wires, everything passed. I removed the driver's door panel and tested the master switch, everything passed. I checked the continuity of the wires coming from the master switch to the passenger switch and everything passed. I checked if there was voltage coming out of the connector leading to the window motor and there was. Today I tested the motor by applying 12vdc directly to it. It went down no problem, but to get it back up, I needed my g/f to help push the window up while the motor was forcing (it was turning but sounded like it was having trouble). The regulator visually looks good with absolutely no rust on it and no rust anywhere else in the door panel. Considering all this, is the reason why my window won't go up is because the motor needs to be replaced? but why does it have no problem going down? anything else I should check? Thanks.

Ya, I don't really think that the problem is electrical either because there's +/- voltage going to the motor. I'll lube them up and see if that works, thanks.