My Creek is doing the same. Bedroom slides in no problem, the two bigger slides don't want to move.
I've turned my valves and never had to reprime?
Make sure you have enough fluid (trans fluid) in the reservoir. The slides may just be sticking and need of some lube, unfortunately I'm no RV repairman or mine would be fixed by now & I would share the knowledge.
In a pinch you can have someone help push the slide from the outside while you push the button to help it start moving.
I was alone and had to use a large 7/8 (I believe) open end wrench to turn the bar that runs between the two slide out tracks under the slide. Once the slide was about 1/3 of the way in the hydraulics took over and the slides closed.
If and when you find the issue please post up & let us know.
2003 cedar Creek 36 RLTS
Pushing an F350 diesel
US Navy Persian Gulf Vet 1991-1994