1967-1972 GM K-Series 4WD Transmission Kits

Toughen your 1967-1972 Chevy or GMC K-Series truck with our PerfectFit™ Overdrive Transmission Kits. We offer the most complete solutions for classic GM 4x4s, including the heavy-duty TREMEC TR-4050 5-Speed Manual with its 6.16:1 crawler gear, and our A41X 4L60E-based 4-Speed Automatic. Our kits are engineered as total systems, ensuring your K10 or K20 gets modern highway driveability and off-road strength. Every component is included for a seamless installation with no hidden costs or missing parts.