i have a 7230R here that had it's hitch slice replaced yesterday. After that neither the hitch or the scv's can lift anything unless the steering wheel is turning. The mechanic came back, removed all the scv slices to make sure that nothing had moved (there's a small valve held by an oring in each. he used grease to make sure they stay put), put them back together and it worked. until this morning. What could it be?