You state the chassis batteries are NEW. How New? Running the engine for 20 minutes puts a larger charge on the batteries to get the 12 volt power to run the Pump for the Jacks. You don't state what brand jacks, but to have enough battery power to retract usually means you have Power EXTEND and Power Retract. It requires the HYD pump to run for both. If you are indeed positive the batteries are fully charged and you have this problem, then you need to check the 12 volt positive battery cable from the HYD pump to its battery connection source. The negative or ground is usually the pump bracket mount bolts where it is bolted to the chassis frame. I would also when you have the problem, engage the Boost Start switch and hold it down and then attempt to retract the jacks. IF THEY OPERATE, then Monaco is wrong and your HYD pump is connected to the coach Batteries. Doug