Sounds like you might have an over service issue. With the jacks fully retracted, ensure the proper tank fluid level.
We had similar retract problems with our last MH that were cured with frequent cleaning of the jack struts(rams) with the same fluid the jacks use...most use ATF(automatic trans fluid). Some owners use WD-40 for cleaning the rams, but that is Water Displacement fluid. Can't go wrong cleaning the rams with the lubing qualities of the fluid the system runs on.
Jan and Bob