Gear Splitter Install

Upon activating the unit with a rocker switch on the dashboard, a solenoid closes a valve, changing a path of oil to hydraulically hold a clutch pack that drives the planetary gears. These gears reduce the drive ratio 22 percent (0.78:1), so you have intermediate ratios to maintain engine rpm at the optimum level. Splitting between the factory gear selections (hence the term "gear splitter") gives you better hill-climbing performance, among other benefits. Other pluses include lower transmission temperatures, improved fuel economy, and reduced noise in the cabin.


Installation of a gear splitter at Gear Vendors typically takes about a half-day or so, and is fairly simple in most applications. You first remove the transmission extension housing and bolt on the Gear Vendors replacement housing which has an eight-hole pattern to receive the overdrive. Then tighten the eight nuts and take the driveshaft with the new yoke (included) to the local driveshaft shop to be shortened (as per the instructions). Plug in the electronics and fill the overdrive with the recommended lube, and you are ready to roll.

Bolt-On Application
On the 2003 3500 Dodge Ram Quad Cab shown here, a show truck nicely customized by Performance West Group, the transmission is a NV5600 manual with the NP 273 transfer case and 4.10 gears. For the show circuit, the truck is a shod with mind-boggling 37-inch tires. On the road, however, it runs on 285/80R17 tires.


Even more impressive is the Cummins HPCR engine pumping out 370 horses and a prodigious 750 lb.-ft. of torque. As big as those numbers are, Gear Vendors has handled much larger levels of power without a hiccup.


As shown in the accompanying photos, the install is a straightforward, bolt-on deal. The Gear Vendors unit is 14 inches long, requiring the two-piece driveshaft to be replaced with a single, shorter one. For this application, the tail shaft on the transfer case is removed and replaced with the Gear Vendors adaptor. One of the most important aspects to keep in mind is precise alignment of the driveline angles to ensure vibration-free operation.