For the purposes and whenever used in this chapter, the following definitions shall have the meanings indicated, unless otherwise required by the context:
When a judge is entitled to include for retirement under the judges' retirement system service as attorney-general or an attorney-general is entitled to include for retirement under the attorneys-general retirement system service as a judge, there shall be transferred from the system the member leaves to the system he enters (1) the whole amount of the member's contributions remaining to his credit, and (2) the members's proportionate share of all other funds paid into the state treasury and held in trust for the retirement system from which he is being transferred during the period he was a member of that system. The sum transferred shall thereafter be a part of the system to which it is transferred and shall be held and dealt with in the same manner as if the member had made his contributions to that system as a member and as if the other contributions had been credited to the system during the time he was a member.
Any judge who becomes a member of the judges' retirement system after April 15, 1970, shall not be entitled to include for retirement as a judge any service as attorney-general rendered after September 1, 1958, unless he was a member of the attorneys-general retirement system for the period of service to be included and has left his contributions in that system until he becomes a member of the judges' retirement system.
Any judge who is a member of this retirement system on April 15, 1970, who does not have twenty (20) years of service when he attains age sixty-five (65) shall be entitled to a credit for service not exceeding four (4) years if he retires on or before his seventieth (70th) birthday; or if he is past seventy (70) years old on April 15, 1970, and retires on or before December 1, 1970, he shall be entitled to a like credit.
Any judge who becomes a member of this system after April 15, 1970, shall not be entitled to full credit for any service rendered after his seventieth (70th) birthday but shall be subject to the provisions for late retirement.
T.C.A. § 17-313