When the second-generation Dodge Ram 2500 heavy-duty pickup debuted for the 1994 model year, the company backed its 5.9-liter Cummins I-6 with the TorqueFlite 47RH four-speed automatic transmission. With its new P7100 fuel injection pump, the engine produced an impressive (for its time) 160 hp and 400 lb-ft of torque. By 2007, output had increased to 325 hp with 610 lb-ft of torque, and the transmission had advanced slightly to the 48RE.

We all know how easy it is to make big power out of a Cummins engine. Bolt up a bigger turbo and a set of high-flow injectors and pair the whole outfit with quality ECM tuning and you’re quickly on the way to quad-digit horsepower. Heading down this path, however, means that it won’t be long until Dodge’s notorious weak-link rears its ugly head. That’s right, one healthy burnout later and snap! You’ve gone from a working transmission to one with all neutrals.

The first step in any performance transmission build is upgrading the friction material and torque converter. Trouble is, once you get everything holding tight, all that torque gets sent to the next weakest link. In the case of the TorqueFlite 47R/48R transmissions, this next point of failure is the input shaft. With all the slippage taken care of, one hard throttle up-shift or forced down-shift with the converter locked is all it takes to snap this shaft. Thankfully, RevMax offers a solution for this with its new 35-spline billet input shaft kit (PN 478-512).

When compared to the best 300M 23-spline shafts, the former gold-standard in the industry, RevMax’s new forged billet 35-spline shaft is 37-percent stronger at both ends. Because the input shaft is larger in diameter, the company had to also reinvent the transmission’s pump stator support and the turbine drive hub within the torque converter. RevMax includes the new pump stator support with the kit, however, the turbine drive hub is sold separately (PN 478-428) for those who don’t already have a 35-spline torque converter.

The RevMax forged billet 35-spline input shaft features a one-piece shaft design and forward hub assembly and offers the largest cross section available on the market today. The forward hub is also designed to accept an additional direct clutch. The pump stator support is heat-treated and ground with a more robust flange designed to reduce distortion and loss of pump volume output. Unlike other designs, the RevMax stator eliminates the seals between the stator and body that can deform. All fluid circuits are cross drilled, threaded, and plugged to eliminate leaking at the checkball location. Custom sized sealing rings are included, and a high-load bronze support bushing is pressed into the support. To get the most out of this kit, RevMax recommends adding its billet forward piston (PN 478-461) as well.

The RevMax forged billet input shaft kit is available for 1993 to 1995 Dodge Ram trucks equipped with the 47RH automatic transmission along with 1996 to 2002 47RE-equipped trucks and 2003 to 2007 Cummins-powered pickups with the 48RE automatic.