JB Conversions Shows Us The Ultimate "Jeep" T-Case
The Dana 300 may perhaps hold the most potential for extreme hard-core use of any stock Jeep transfer case. It has all-gear innards, along with a compact case that fits between the stock framerails of early Jeeps. Good cases are readily available in junkyards, or your Jeep may have come with one stock. Add to that the fact that JB Conversions offers the parts and pieces to build your Dana 300 into a trail slayer with upgraded 4:1 gearing and 32-spline front and rear output shafts or as a complete assembled unit delivered to your door for half the price of a similar aluminum aftermarket T-case, it's hard to pass up. Even later-model YJ and TJ guys looking to swap in a passenger-side drop axle would be wise to consider a 300 as a viable alternative to an aluminum T-case.
Follow along as JB Conversions builds a Dana 300 for our '53 flattie. We didn't need to do the 4:1 gears because we run extremely low axle gears and have a granny First gear in the SM420, but we did want the throttle-proof, 32-spline front and rear output shafts and twin-stick capability that our new JB Conversions Ultimate 300 offers. No longer is our use of the throttle limited by our Spicer 18's weenie 10-spline outputs.
To mate our new Dana 300 to our SM420, we ordered a Novak Conversions adapter kit (PN 423). The kit included a new 10-spline input shaft that easily bolted in our new Dana 300. In addition to being made of superb material, the aluminum adapter is a miniscule 3.2-inches long and allows three clocking positions. We were able to use the adapter's existing holes to clock the Dana 300 in the same orientation as our Dana 20/Spicer 18 hybrid (Dana 20 case with Spicer 18 gears and shafts).
Size-wise, the Dana 300 was nearly identical to the Dana 20 case it replaced. We just needed to do a bit of gentle clearancing with a hammer to the floorboard that resulted more from the clocking than the size of the case. After the install, we still have the same amount of room between the framerails and the T-case. In fact, we were able to reuse the custom crossmember we had built for our old T-case. All we needed to do was cut the mounting tabs from the frame and reweld them farther forward.