Powerglide

1.58 Ratio Extreme Planetary Assembly Kit
Part No. 28158G-06

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Sonnax offers complete GM Powerglide planetary assemblies in a variety of gear set options and configurations to ensure you get the performance you want without overpaying or sacrificing quality. Each comes fully assembled and ready to install.

Track-proven to 3,000 HP, Sonnax Extreme planetaries are the finest quality Powerglide planetary assemblies in the world. From carrier and output shaft to gears and thrust washers, every component is refined for maximum durability in the most demanding applications. The ring gears are even pre-drilled for the Sonnax stabilizer system to prevent vibration and broken reverse friction plates. Extreme gear sets feature Sonnax premium sun and pinion gears that also undergo the same advanced processing used in Formula 1, NASCAR® and other high-end professional racing circuits.

1.58 ratio Extreme planetary assembly kit 28158G-06 delivers tunable control right at the start, when traction can make or break a race. The one-of-a-kind Sonnax 1.58 is designed to fit into existing Powerglide cases, allowing racers to achieve the lowest numerical ratio available for the Powerglide without the hassle and expense of converting to a TH400.

  • Direct replacement, requires no special assembly or case modification
  • Top-quality sun and pinion gears undergo additional advanced processing for unmatched durability
  • Extreme strength output shaft delivers unrivaled performance and reliability
  • Compatible with the Sonnax big input shaft system to handle the most extreme horsepower
  • Includes high-capacity reverse clutch assembly
  • 24-Tooth billet drum flange designed to work exclusively with Sonnax clutch drums
  • Bolt-together carrier for ease of service

The 1.58 gear set has had a significant impact on helping my racing program this year and played a big part in our being able to win two races and be more competitive. It has enabled us to have a much greater tuning window and allowed us to apply the power from the engine more efficiently. The 1.58 has over 50 passes on it and is still going strong. Thank you to Sonnax for making such a great product and for developing new transmission parts so that we as racers can continue to improve and go faster.

K. Ashley Kevin Ashley Racing Newark, DE

See chart and specs below to determine if this planetary assembly suits your application, or dial in options here to choose your build.

Contender

Track-Proven to 1,500 HP

Premium

Track-Proven to 2,000 HP

Extreme

Track-Proven to 3,000 HP

Sonnax Warranty 1 Year (Gears Only) 2 Years (Gears Only) 2 Years (Gears & Shaft)
Gear Material 9310 Suns
8620 Pinions
9310 Suns
9310 Pinions
9310 Suns
9310 Pinions
Gear Process Premium Premium Advanced (Learn More)
Shaft Material Long Shaft = 4340
Short Shaft = HY-Tuf
Long Shaft = 4340
Short Shaft = HY-Tuf
300M
Shaft Splines Cut Spline Cut Spline Rolled Spline
Thrust Washers OE Steel-Backed PTFE Steel-Backed PTFE
Ring Gear Standard Standard Maximum Duty

Applies to planetary assembly kits only

  • Carrier Assembly & Output Shaft OE Length, 300M Shaft
  • Front Sun Gear & Drum Flange 24-Tooth
  • Ring Gear
  • Reverse Clutch Piston with Seals 2 Seals
  • Reverse Clutch Piston Plate
  • Reverse Clutch Pressure Plate
  • Reverse Clutch Frictions (7)
  • Reverse Clutch Steels (8)
  • Gear Process Level: Extreme
  • Shaft Length Option: OE
  • Shaft Material: 300M
  • Ratio: 1.58
  • Flange Tooth Count: 24

  • Powerglide 1.58 Ratio Extreme Planetary Assembly Kit 28158G-06
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