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47RE, 47RH, 48RE

Smart-Tech® Big Input Shaft Kit
Part No. 22121B-08K

Use of this kit requires installation of matching Sonnax performance converter kit BW-RK-4 or BW-RK-5.

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The Sonnax Smart-Tech® big input shaft kit 22121B-08K is the ultimate solution to prevent input shaft spline-twist and breakage in high torque Chrysler 47RH, 47RE and 48RE diesel applications. Compared to the best 300M 23-spline shafts, the Sonnax input shaft is 35% stronger at both the spline portion of the shaft and the sealing ring/cross-hole area of the shaft, eliminating all concerns of failure at these critical points.

The larger sealing ring and cross-hole area requires a custom stator/pump cover assembly. The stator assembly features standard 48RE tube splines made of high-strength steel, improved retention in stator body, 48RE matched pump porting and special rubber seals to eliminate oil leakage between cover and pump body.

The longer direct (front) clutch hub portion of the shaft has longer splines that allows for one extra (OE-thickness) direct friction plate when used with included thinner billet aluminum direct piston, all while keeping OE-thickness steels, backing plate, OE waved retaining ring and OE clutch clearances.

Some common aftermarket modifications designed to include extra clutches require reduced steel thickness and decrease the heat absorption capacity of the clutch pack, others reduce clearance and eliminate the waved retaining ring, which contributes to excess 2-3 shift overlap. The Sonnax kit avoids these problems by increasing the number of frictions from five to six, adding to the steel mass of the clutch pack, and maintaining the OE thickness backing plate and clearances for the optimum combination of increased capacity and durability.

  • Extreme duty, 1-1/8” diameter 35-spline input shaft
  • .100” larger diameter at sealing ring cross hole area
  • Shaft custom forged from ultra-high strength 300M steel
  • One-piece shaft design eliminates weak connection between shaft and clutch hub
  • Keeps OE oil flow paths and flow area for predictable lockup, apply and release
  • Input Shaft  35 Spline with Extended Hub
  • Stator Support Assembly
  • Direct Clutch Piston
  • Steel Clutch Plate .068" Thick
  • Seal Rings 1 Extra
  • Quad Ring Seals (4)
  • 47RE, 47RH, 48RE Smart-Tech® Big Input Shaft Kit 22121B-08K
  • 47RE, 47RH, 48RE Smart-Tech® Big Input Shaft Kit 22121B-08K details