Mile Marker
501 Hubs Service Kit 
Convert your full-time NP203 transfer case to part-time with the Mile Marker 203 Conversion Kit (PN: 501). Proven for over 40 years, this durable wedged-gear kit improves fuel economy, tire life, and handling—without complex modifications. Easy to install with common tools, it eliminates thrust stress and oiling issues, delivering smoother performance and longer drivetrain life.
Military Grade
12-Volt Electric Winch
4-Bolt Pattern
*Customized products can take an additional 4-6 weeks to ship.
Quantity
1-5 Business Days Delivery (USA Only)The Mile Marker 203 Transfer Case Conversion Kit (PN: 501) is the ultimate upgrade for converting your full-time NP203 transfer case to part-time use—without the need for complicated modifications. With over 40 years of proven performance in the field, this wedged-gear conversion kit delivers all the benefits of high-end conversions while eliminating the downsides of crown gear-type setups. Its precision bearing serves a dual purpose: maintaining smooth operation and proper gear alignment. The result? Stronger performance, longer drivetrain life, and a cleaner, simpler install—with no thrust applied to the bearing and no need for extra oiling elbows.
Engineered for real-world use, this kit can boost fuel economy by up to 30%, reduce tire wear, improve handling, and extend drivetrain life. Installation is straightforward, requires only common tools, and fits all NP203 transfer cases. Whether you're restoring a vintage 4x4 or prepping your rig for serious off-road terrain, the Mile Marker 203 Conversion Kit delivers trusted durability and trail-ready performance.
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