The motor is still the stock 4.0 V6 with some bolt-on mods. Cold air, aftermarket TB and MAF sensor (supposed to be better flow, but I think I got ripped off) headers, custom X-pipe exhaust, and EGR deleted.
Trans is a factory 5R55E 5-speed auto. I put in a shift kit and upgraded the pump and torque converter to heavy duty. It works really well! Probably the best money I spent.
Transfer case is still the stock electric shift Borghese Warner unit. Haven't had any trouble with it, so it stays for now.
Custom tuning from SCT and Explorer Express makes it run without missing a beat. I will be keeping this setup until the motor or trans craps out, then it will put in the Explorer 5.0 V8.
The front axle is a Dana 44 from an unknown donor. Limited slip diff and 4.88 gears. It has the unit hubs on it, so it's not the best option, but it has worked fine for the last 8 years or so. Flexy Jeep Wagoneer leaf springs and long travel Bilstein 5100's hold the front end up. A Toyota steering gearbox and custom tube/heim steering links in the usual crossover configuration for the steering.
The rear axle is a 9" also from an early Bronco with matching 4.88 gears and Detroit locker. I grafted in some taller and longer 63" springs from a Chevy Truck to get the lift and flex I wanted. I still had to use the factory 2" lift blocks to level it out. Long travel Bilsteins out back as well.
I can say with much pride that I have owned this truck since new and have about 180k very hard miles on it and NOBODY but me has ever touched a tool to it or struck an arc on it.