Muscle car enthusiasts have enjoyed upgrading the transmissions in their vehicles for years. Due to the added complexity of four-wheel drive trucks, kits for adding aftermarket overdrive transmissions have been limited, if not non-existent. American Powertrain has just announced a square-body Chevy/GMC four-wheel-drive kit based around the heavy-duty TREMEC TR-4050 five-speed transmission. The four-wheel-drive manual transmission kit is designed to fit 1973 through 1987 Chevy and GMC square-body pickups and SUVs, including Suburban, Jimmy, and Chevy Blazer.

Everything needed for the installation is included in the kit, which features the TREMEC TR-4050 five-speed transmission capable of handling torque loads up to 600 lb-ft. The comprehensive kit also includes a CNC-machined, aluminum bellhousing, Hydramax hydraulic clutch assembly, flywheel and bolts, transmission mount, pilot bearing, harness, shifter, shifter knob, adapter for 10-spline NP205 transfer case, and all necessary hardware.

The kit includes everything necessary to do the installation including the bellhousing, hydraulic clutch throwout bearing, and transfer case adapter.

This kit is designed to make use of the heavy-duty transmission’s low gearing to assist in handling larger tires and high torque loads. Drivers can also see a 30-50% increase in fuel economy, thanks to the low RPM cruising. Additional benefits are reduced engine wear and cooler engine operating temperatures, as well as an improved driving experience thanks to greatly reduced driver fatigue.

The transmission is fully synchronized for smooth, quiet operation and has the standard right-hand, six-bolt PTO, which offers the ability to run hydraulic pumps. American Powertrain also offers shifter and clutch options as upgrades. If you are not sure what exactly you need for the conversion, give American Powertrain’s technical sales staff a call at (913) 646-4836. For more information about American Powertrain’s 1973-87 Chevy/GMC square-body, four-wheel-drive, five-speed kit, check out the company’s website.