Front Output Beef
Most early NP205 units came with the 10-spline, 1.25-inch front output shaft. Later ones came with a 30-spline, 1.25-inch shaft which is stronger, but it still isn't the best available. For serious beef we chose the 32-spline, 1.401-inch shaft, which was found in many Ford and Dodge versions.
The 10-spliner is used for a 1310 series U-joint or CV, or a 1350 U-joint. The 30-spline worked with a 1310 CV or the 3R CV, or Saginaw type. The burly 32-spline can use a yoke for a 1310, 1330, or 1350 CV or U-joint, and even the 1450 size joint and a few other weird options. If you need the strength of the biggest, this is the one for you.
Gender Changes
The input gears available for the 205 are many, but the main differences are male (external splines) and female (internal splines). The NP205 used these three female input gears. From left to right: Long 32-spline for the TH400 and some late SM465 trannies, short 32-spline for the TH400, and the 31-spline for Ford applications. The transmission output shaft fits directly into the input gear without a sleeve for the best arrangement, with no extra slop to develop from a sleeve. We chose the short 32-spline for our bulletproof 205.
GM also used external-spline input gears, which required the use of a sleeve to couple to the transmission. From left to right: Fixed yoke for remote use, 10-spline for the early SM465 manual transmission, 27-spline for the TH350, and 29-spline for the early Dodge diesel manual applications. Not shown here is the 23-spline for Dodge gas engine and diesel automatic applications.
Twin-Sticking It
The standard 205 shifter is a single lever running two shift rails to provide high 2WD, high 4WD, neutral, and low 4WD. These shifters aren't available anymore, but Performance Gear & Axle makes its own stock-style replacements for Ford, Chevy, and Dodge applications. In a stock 205, the interlock pin between the shift rails prevents any other combo of positions, which is both good and bad. We like to have independent control of the rails so we can have the same positions as stock, but also have low rear-wheel drive only, and low front-wheel drive only. But simply removing the interlock pin will allow the case to be put into high and low range at the same time, which is not a good thing.
By modifying the rails properly you can get high, neutral, and low out of both the front and/or rear output, without having one in low and the other in high. Both range and mode shafts should be modified, but we decided a set of modified rails from Off Road Design was best, as the detents and reliefs are machined to precision, rather than just guessing at what approximate amount to grind off. With ORD's twin-stick conversion, we'll have every option we need. If you must do it yourself, check out "Twin-Stick 205", an article about homemade twin-stick mods to do the same thing.