The 7.3L Powerstroke in your 1999 to 2003 F250 or F350 can handle modifications all day without even a grumble. However, your truck's transmission is not so fortunate and will need at least a few parts, if not a complete replacement, in order to keep up with your engine's extreme power potentials. The good news it that the aftermarket is huge for your truck's 4R100 automatic transmission and we here at Stage 3 have a full lineup of torque converters, transmission coolers, and even a few fully-built performance 4R100s that can handle much higher horsepower and torque outputs than stock to keep your drivetrain running at its best. Your truck's stock torque converter is usually the first thing to go, so make sure to grab as soon as you start using any of our 7.3L Powerstroke performance upgrades. Once you have your transmission situated, take a look at our turbo upgrades!