GM 4WD Manual & Automatic Transmission Conversion Kits

Toughen your Chevy or GMC truck with our PerfectFit™ 4WD Overdrive Transmission Kits. We offer the most complete systems for GM 4x4s, featuring the heavy-duty TREMEC TR-4050 5-Speed Manual with its 6.16:1 crawl ratio, or our proprietary A41X 4L60E-based 4-Speed Automatic. Our kits are engineered as total solutions, including all necessary components for a seamless installation. Upgrade your GM 4WD with modern overdrive strength and highway driveability without the hidden costs or missing parts found elsewhere.