American Powertrain™ Introduces Pro Fit TKX 5-Speed and Magnum 6-Speed 2WD Conversion Kits for 1999-06 Chevy/GMC NBS GMT800 Trucks
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Now in stock. Designed to keep the stock appearance with precision fit.
COOKEVILLE, TN (March 25, 2026) – American Powertrain™, a leading source for modern overdrive systems, announces there’s more fun on the horizon for anyone with a 1999-06 Chevy/GMC new body style GMT800 truck. American Powertrain now offers a TKX 5-Speed and MAGNUM 6-Speed Pro Fit Transmission Conversion Kit, for any 1999-2006 NBS, 2WD Chevy or GMC truck as a turnkey solution with minimal tuning required.
Both the 5-speed and 6-speed options preserve the look and feel of the truck’s stock interior. Engineered with a mid-mount shift location and a specially designed UnderDash Hydraulics bolt-on truck pedal, this conversion to a 5-speed or 6-speed offers the best of both worlds – NBS stock and the pleasure of driving with a stick for the ultimate in control and in time for spring cruising with savings to fuel economy of 30 to 50%. Other advantages are reduced noise, vibration, and harshness, cooler engine operating temperatures for a reduction in engine wear, and longer engine life.
Both kits are engineered for efficiency and precision, featuring a streamlined case designed for a fit that requires absolutely no cutting of the floor, tunnel, or chassis. Both kits offer multiple gear ratios as options.
“The GMT800 platform has a massive enthusiast following, and owners have been asking for an option to add a 5 or 6-speed that would maintain the truck’s stock look and feel,” says Matt Graves, American Powertrain Marketing and Product Manager. “This kit delivers on so many levels, and with today’s fuel prices, it almost will pay for itself with the fuel economy alone. We have these kits in stock, so now’s the time to give us a call.”
Optional parts include Hydramax hydraulic clutch, specialized bell housing, flywheel, and shifter and shifter handle upgrades, pilot bearing, and more. Automatic-to-manual conversions will need some slight ECU tuning to keep the engine out of limp mode. To learn more view this video below.
For more information or to receive a custom quote, visit American Powertrain at americanpowertrain.com, or speak with one of American Powertrain’s sales technicians at 931-646-4836.
American PowertrainPro-Fit MAGNUM 6-Speed Transmission Conversion Kit for 1999-2006 2WD Chevy and GMC NBS GMT800 trucks
ABOUT AMERICAN POWERTRAIN™ American Powertrain exists to help muscle car owners equip their cars with modern drivetrain technology, offering overdrive transmission systems, hydraulic clutch kits, and a wide range of drivetrain-related parts from diff to block. Since American Powertrain opened for business, we have quickly become the world’s largest TREMEC dealer. Our installation parts and systems are proudly made in America for unmatched quality. Our staff of highly experienced enthusiasts has years of experience helping car owners and builders make the right drivetrain choices.
