Slider is stuck, what now?

Ok, I got on here Saturday eve and posted that we had gone up, met the local rv mechanic and got the slides back in, although it was manually done by hand (and back)work. He told me he thinks the pump section is bad, since the motors humming and it actually does pull the piston in when it's not attached. The other two slides had to be pushed, too, although we could see the BR piston move in it's 'free space' between the nuts. The pump and system is Dewald, 3b or 4b, I believe. Single switch powers all three slides, and it has a cable system to keep it aligned. I've done some research and found the trouble shooting manual on how to check both the pump and the 3 cylinders. Anyway, we got it home, and have spent today cleaning and checking it out. So, per the slides, I'm going to try to find the pump seal kit and see if I can rebuild it, otherwise I'll buy a new one. In a day or so, I'm taking it out to our rv shop here in town and let them go over it and see what they can find. For sure it needs a bottom slide seal on the on that wasn't retracting, since there's no sign of any seal at all down there. (The opposing side slide needs one too, but just because it's got the crinkled spaghetti look to it). Also found that the PO's were total park campers, because the shurflo pump I found in the front utility compartment is toast, and when I checked under the kitchen cabinet where it's supposed to be, there was none there, along with the outside shower plumbing, and the pex line had been re-run to bypass the pump for use with city water. Ordered a pump and filter today, along with a new outside shower panel and replacement blinds for a few windows that are missing them. Then wash the beast. Then check the furnace and stove and hot water heater. But it sure did ride well on the long trip (2 hours) home! :)