Have a ZD 28 with the built in jack. Trying to lift the mower to access the blades for the first time. Purchased this unit recently and the handle for the built in jack was missing. Ordered a handle, pulled pins and tried to lift but no luck. Seems like some threads are stripped or the adjuster is out of sorts. I can thread and unthread the adjuster by hand but as soon as the weight of the mower is put on the Jack it stops threading. Any way to adjust/diagnose/repair this issue. Any help is appreciated.