The Pentagon announced yesterday that the Rapid Deployment Force will be transformed into a separate and independent command for operating forces of all the services in the Persian Gulf.

Defense Secretary Caspar W. Weinberger said it would take three to five years for the RDF to evolve into the elevating status of a separate unified command. Officials said they hoped the command could be placed in or somewhere near Southwest Asia.

In the meantime, the RDF will remain at MacDill Air Force Base in Tampa, where it has been under Gen. Volney Warner, commander of the U.S. Readiness Command. Under the new setup, the RDF will move out from under the Readiness Command both in peacetime and in war.

There has been considerable professional friction between Warner and Marine Lt. Gen. P. X. Kelley, RDF commander. Under the old setup, Kelley would have become RDF field commander only in wartime.

As a first step toward making the RDF an independant command, Weinberger said the Army's 18th Airborne Corps -- consisting of the 82nd Airborne Division at Fort Bragg, N.C., and the 101st Airborne Division at Fort Campbell, Ky. -- will be formally designated as part of the RDF. Those outfits have been on call for RDF Persian Gulf duty, as well as for NATO emergencies, in the past.