1991 GMC GMC 2500 PICKUP - Transmission, Transaxle Automatic Transmission, 4x2, 4L80E Opt MT1, Gasoline, 4.3L, 60 Months Warranty. Free Shipping, 1 Month Return Policy. Used (Original Equipment Manufacturer). Transmission Tested and Run, covered by warranty. All Transmissions are Shipped as Complete Assemblies including: Transmission; Torque Converter (Automatic Transmissions Only); Oil Pan.