Dubbed ‘i’ for integrated, the BlackBox-i is the second evolution of the underdrive series. Designed to be as short and compact as possible, the BackBox-i was specifically developed for short wheelbase vehicles; jeeps, early broncos, and rock buggies. To meet these goals, the design process had to start with a clean slate.
Setting aside all previous notions of gearbox fitment, we removed the typical male/female splined connection at the transfer case saving up to 4”. Having done away with the stock transfer case input shaft, we replicated its internal dimensions right into the back of the BlackBox’s mainshaft. This allows the Blackbox-i to fit inside and fully integrate into the transfer case, saving a dramatic amount of gearbox assembly length.
Replacing the input shaft and housing, the Dana 300 input gear directly splines onto the BlackBox output shaft, making this a very compact 5” long BlackBox-i. Need to adapt to a different transmission? The BlackBox’s wide variety of input shafts takes care of it at the same time.
Bronco Dana 20
Replacing the long factory input shaft and bearing retainer, the 6-spline input gear mounts directly to the Blackbox output Shaft. This adds up to a compact 5.188” long gearbox assembly that can now also be easily adapted to a wide range of transmissions.
Atlas II - The Shortest
The BlackBox-i for the Atlas-II replaces the stock Atlas input shaft, as well as the 1” thick bearing retainer and clocking ring. This system only adds 4” over the stock Atlas-II! The BlackBox-i for the Atlas is compatible with all gear ratios, and the older 6 spline, the newer 32 spline and the Newest 8 Bolt 32 Spline input gears.
Hero 2 & 3 Speed
The BlackBox-i for the Hero 2 & 3 Speed Transfer Case replaces the stock Hero input shaft, as well as the 1" thick bearing retainer and clocking ring. This system only adds 4" over the stock Hero Transfer Case! The BlackBox-i is compatible with all gear ratios but does require the input assembly to be shipped to us for gear to be installed. (Yes this turns a 3 Speed into a 6 Speed!)