This GM automatic was commonly found stock in vehicles from 1969-81.
These lengths of the tail housing are 6, 9, and 12. Advance Adapters GM TH350 Transmission To Dana 18/20 Transfer Case Adapter - 50-3000 The adapter kit includes a adapter housing, new 4wd TH350 output shaft, 6 spline spud shaft, nylon bushing, bearing, snap ring, O-ring, seal, gasket, fastening hardware and adapter instruction. the transfer case bore size (3-1/8) small hole or (4) large hole for proper retainer. GM TH350 3 speed, 2wd automatic transmission to the Jeep/Scout Dana 18 and 20 transfer case;Transfer Case: Jeep Dana Spicer 18 or 20 (6 spline input);Transmission: GM TH350 (2wd);California Residents: WARNING The output shaft length corresponds with these tail housing lengths.