Okla. Stat. tit. 46, § 46-8: Grant intended as mortgage recorded as mortgage

Every grant of real property, or of any estate therein, which

appears by any other writing, to be intended as a mortgage within

the meaning of this chapter, must be recorded as a mortgage; and if

such grant and other writing explanatory of its true character are

not recorded together at the same time and place, the grantee can

derive no benefit from such record.