When it comes to choosing transfer cases, the NP205 has always been known as the king of strength. From big-truck mud bogging with 44s to stadium sled pulls, the 205 is the transfer case that answers the call when nothing else will do. Fitted in Chevy, Dodge, Ford, and International pickup trucks during the 1970s and 1980s, these units are compact, geardriven, iron-cased, no-nonsense, and reliable workhorses of the 4x4 world. As good as this unit is, the drawback to the 205 is the poor gear reduction in low range. With a stock reduction ratio of 1.96:1, the crawling capability for the 205 is nothing to rave about. It's adequate for most trail usage, but lower gears have been on the wish list of wheelers for years. Other popular but chain-driven transfer cases, such as the NP241 and NP271, have been the lucky recipients of 2.72:1 gears. The reason that lower gearsets (which have larger-diameter gears) have not been made for the 205 is that the stock case is simply too small-the larger low-range gears won't fit inside.
The LoMax 205 gears are designed to improve strength and lower the ratio. The new low-range output drive gears (right) are wider than stock, and this longer tooth face increases the shear resistance of the gear tooth. When lowering the ratio of a gear, the shape and profile of the teeth need to be strengthened as well as the shafts and hubs. This counters the weakening effect often seen with some gear kits that simply lower the ratio. | 
Case width and height of the new unit is the same as OEM, assuring a stock fit between the framerails of Chevys. The LoMax iron case and gears are only five pounds heavier than stock. While only Chevy units are available, JB Conversions plans to investigate Ford-style drops as well. Note that the PTO provision is also eliminated on the new case, since most of off-roaders don't use the PTO anyway. | 
The front of the LoMax case provides bolt patterns for the common GM figure-eight pattern and the later round six-bolt pattern. The round pattern is a dual form allowing higher positioning of the front output shaft and improved ground clearance. Another use for the LoMax case is for, strangely enough, stock gears. The round pattern GM205 case is as rare as hen's teeth, and the LoMax case is a direct swap. If you have a figure-eight case and are looking for an easy swap to a round-pattern application, the LoMax case can be used with stock NP205 gears. |
Luckily, JB Conversions has countered the case-size limitation by making a brand-new design nodular-iron case, as well as the larger LoMax 3:1 gears that go inside it. JB Conversions began offering high-strength gearsets for the Dana 300 several years ago with great success, also marketed under the LoMax name. But for big trucks or high-horsepower applications, the 205 with these new low gears is the way to go.
Mounting the LoMax 205 to a GM NV4500 requires only one minor modification. The 32-spline output shaft is a perfect match to the LoMax input gear. The NV4500 tailhousing must be notched in this area to clear the shift rod (arrow). Adapters aren't needed for this swap since the LoMax case has the GM "round" bolt pattern along with the figure-eight pattern. | 
An optional, heavy-duty transmission-mounting boss is integrated into the steel inspection cover. This mount is not required but can be a significant support point for the weight of the 205. All of the other external stock 205 parts fit right on the LoMax case. | |
The LoMax kit comes with a new case, cover, and five full gearsets. To keep the cost down, the new case accepts all of your original New Process parts such as output shafts, shift rails, and bearing retainers. However, complete new units are available if you don't have an NP205 already. If you are installing a LoMax 205 in an existing stock application, there are no speedometer, floor board, tranny mount, or driveshaft modifications needed to accommodate it. This means there is no other cash to spend. Other aftermarket transfer case installations can cost several thousand dollars more when considering new adapters, driveshaft, exhaust work, and so on. There is absolutely no fabrication required to install the LoMax 205, and single- or twin-stick kits are a available as well. On the downside, for now, the new case is configured for GM passenger-side applications only. Cases for the Ford guys will hopefully follow soon.