Okla. Stat. tit. 20, § 95.8

A. An associate district judge may hear any case not assigned or assignable to him under local court rules (a) upon request of any party where the suit is uncontested or (b) where the parties agree in writing any time before trial to having the case heard by him. B. The provisions of this section shall not be interpreted as (a) invalidating any order signed by an associate district judge prior to the effective date of this act or as (b) requiring the judgment roll to affirmatively show compliance with any of the provisions hereof.