GM TH400 Transmission To Dana 18/20 Transfer Case Adapter Fits 1941 to 1979 CJ;GM TH400 automatic transmission to the Jeep Dana 18/20 transfer case (with 6 spline drive gear) adapter kit;Transfer Case: Jeep Dana Spicer 18 or 20 (6 spline input);Your Transmission: GM TH400 (2 Wheel Drive),GM TH400 (4 Wheel Drive) Advance Adapters Advance Adapters GM TH400 Transmission To Dana 18/20 Transfer Case Adapter - 50-1300 50-1300 Transmission Adapters