estimated cost to replace the oil pump on 1997 Ford Explorer

The oil pressure is beginning to fluctuate and a mechanic suggested this may be the oil pump beginning to fail. What is the estimated labor time and cost to replace the oil pump on my 1997
explorer with 5.0L engine and full time four wheel drive?

Asked by for the 1997 Ford Explorer
Before you do that I would try to hook a manual gauge and check the oil pressure and make sure you dont have a faulty switch
Ok Honest--but I hve the same question. If it is the pump what is a ballpark figure?