6L80, 6L90 300mm Converter Heavy-Duty Builds Explained

Presented by Sonnax

If you're interested in upgrading the torque converter in a GM 6L80 or 6L90 transmission, watch this video. You'll learn about the critical weak points of the stock-size, 300mm units and the difference between performance and heavy-duty converter upgrades. To understand options for good/better/best builds, you'll get a closeup look at key components like the front cover, piston and clutch plates, plus unique features of Sonnax multi-plate performance converter kits — the ultimate way to maximize reliability in JMBX, JMBV, JMDZ and JMDY coded units.

For a quick overview of build options, check out this guide to Sonnax 6L80/90 300mm converter upgrades.

Related Units

Related Parts

Required

Recommended

6L80, 6L90 (300mm), 6L80, 6L90 (300mm), Multi-Plate Performance Converter

JMBX Performance Converter Kit GM-RK-21

For street/strip and towing applications.

• Transmission Unit: 6L80, 6L90
• Core: GM 300mm
• Dampered: Yes
• Lockup: Multi-Plate
• Unit Size: 300mm
• Clutch Material: Woven Carbon
• Turbine Hub Input Spline Count: 36
• Bolt Circle Dia.: 11.06"
• Assembled Height: 6.180"
• Bolt Count: 3

Required

Recommended

6L90 (Captive Clutch Conversion), Multi-Plate Performance Converter, 6L90 (Captive Clutch)

JMDZ Diesel Performance Converter Kit GM-RK-22

For diesel and towing applications.

• Transmission Unit: 6L90
• Core: GM 300mm
• Dampered: Yes
• Lockup: Multi-Plate
• Unit Size: 300mm
• Clutch Material: Woven Carbon
• Turbine Hub Input Spline Count: 36
• Assembled Height: 6.543"
• Bolt Circle Dia.: 11.50"
• Bolt Count: 6

Required

Recommended

6L90 (Captive Clutch Conversion), Multi-Plate Performance Converter, 6L90 (Captive Clutch)

JMDY Performance Converter Kit GM-RK-24

• Transmission Unit: 6L90
• Core: GM 300mm
• Dampered: Yes
• Lockup: Multi-Plate
• Unit Size: 300mm
• Clutch Material: Woven Carbon
• Turbine Hub Input Spline Count: 36
• Bolt Count: 6
• Assembled Height: 6.180"
• Bolt Circle Dia.: 11.06"

Required

Recommended

6L80, 6L90 (300mm), 6L80, 6L90 (300mm), Multi-Plate Performance Converter

JMBV Performance Converter Kit GM-RK-23

• Transmission Unit: 6L80, 6L90
• Core: GM 300mm
• Dampered: Yes
• Lockup: Multi-Plate
• Unit Size: 300mm
• Clutch Material: Woven Carbon
• Turbine Hub Input Spline Count: 36
• Bolt Circle Dia.: 9.21"
• Bolt Count: 3
• Assembled Height: 6.271"

While Sonnax makes every effort to ensure the accuracy of technical articles at time of publication, we assume no liability for inaccuracies or for information which may become outdated or obsolete over time.