I see you have a 2006 Mountaineer. What type of slides do you have? I would guess hydraulic but it would be just a guess. You can move the hydraulic systems mechanically using a drill motor and a 1/4" hex head drive inserted in the end of the pump motor.
But if the pump mechanism seems to try to work, it might be better to figure out why it isn't successful. Since you have a 2006, I would first check the self resetting circuit breaker (likely a 30 or 40 amp version in that old of a rig). They are the most common cause of slides not moving or moving intermittently.
Here are some manuals that may help
https://www.montanaowners.com/forums...?do=file&id=23
https://www.montanaowners.com/forums...?do=file&id=23