🔥 Twisted Street™ 6L90E Performance Transmission — 600 HP

Heavy-Duty From the Factory. Updated the Twisted Torque™ Way.

The Twisted Street™ 6L90E is our entry-level heavy-duty performance transmission for GM trucks, vans, SUVs, and muscle cars equipped with the factory 6L90 six-speed automatic.

GM used the 6L90 behind everything from 6.0L and 6.6L heavy-duty work trucks to the supercharged Camaro ZL1. We take that factory foundation and correct its known weaknesses with updated clutch parts, improved pressure control, a NEW Pump & Bellhousing Assembly, and a Super Duty Billet Cover Torque Converter — INCLUDED.

Every transmission is completely torn down, cleaned, inspected, and rebuilt in-house with high-energy performance clutches, new matched steels, updated internal parts, and corrected valve-body operation.

Built for stock and mildly modified applications requiring dependable shifts, stronger converter construction, and heavy-duty service.

Target Performance Rating: Up to 600 Engine HP — Subject to Application Approval

⚡ TEHCM PROGRAMMING — INCLUDED

Every 6L90E includes a programmed TEHCM matched to your application. Factory replacements are programmed using your vehicle's VIN. Engine swaps may require a compatible donor VIN or base calibration. Need a BLANK, unprogrammed TEHCM? Just let us know when ordering. Installation Fast Learn or additional vehicle tuning may still be required.

⚙️ TWISTED STREET™ 6L90E BUILD SPECIFICATIONS

✔ Complete Teardown, Cleaning & Inspection

Every transmission is stripped down to the bare case.

Clutch drums, shafts, hubs, planetary gearsets, bearings, and internal parts are cleaned and inspected for cracks, damaged splines, worn bearing surfaces, and excessive wear before assembly.

✔ NEW Pump & Bellhousing Assembly

Every Twisted Street™ 6L90E receives a NEW Pump & Bellhousing Assembly, not a reused or resurfaced original.

The new assembly replaces common pump wear points that can cause low clutch pressure, slipping, delayed engagement, and poor lubrication.

✔ High-Energy Performance Clutches & NEW Steels

New high-energy performance friction plates and matching steels are installed using the correct 6L90 clutch arrangement.

The 6L90 was built with more clutch capacity than the 6L80 in several areas. We retain the correct heavy-duty 6L90 configuration rather than installing thinner plates or mixing 6L80 clutch stacks.

✔ Updated 1-2-3-4 Clutch Assembly

New performance frictions, matched steels, and strengthened apply piston.

Builder Spec: Sonnax #104984-01 Heavy-Duty Billet 1-2-3-4 Apply Piston, or approved equivalent.

The original cast piston is known to crack, causing pressure loss and slipping in forward gears.

The drum, snap-ring grooves, wave plate, and retainers are checked for the proper updated arrangement.

Clutch clearance is measured and set during assembly.

✔ Updated 3-5-Reverse Clutch & Drum

The 3-5-Reverse clutch is rebuilt with new high-energy performance frictions and matching steels.

Drum welds, snap-ring grooves, retaining rings, apply piston, and sealing surfaces are checked for cracks and wear.

Factory drum and wave-plate updates are installed where applicable.

Builder Note: Use the correct 6L90 clutch count and apply arrangement. Do not substitute the 6L80 high-capacity apply-ring setup without confirmed compatibility.

Clutch clearance is measured before assembly.

✔ Updated 4-5-6 Clutch Assembly

The 4-5-6 clutch receives new high-energy performance frictions, matched steels, and upgraded apply parts.

Builder Spec: Sonnax #104960-01K Heavy-Duty Apply Piston & Backing Plate Kit, or approved equivalent.

The factory apply-piston arrangement and backing plate can flex under load, causing uneven clutch pressure and burned friction plates.

The updated piston and backing plate provide more even clutch application while retaining the factory-style 36-tooth clutch arrangement.

Standard Street retains the correct 6L90 clutch count and factory-style intermediate shaft/hub configuration.

The shaft and hub weld, splines, clutch drum, and retaining parts are inspected. Worn or damaged parts are replaced.

✔ Updated 2-6 Clutch Assembly

The 2-6 clutch is rebuilt with new performance frictions, matched steels, and updated parts where applicable.

The apply piston, seals, and related parts are inspected.

Clutch clearance is measured before assembly.

✔ Updated Low/Reverse Clutch & Sprag

The Low/Reverse clutch receives new frictions, steels, and seals.

The sprag, races, end caps, and retaining parts are checked for wear or damage.

Builder Reference: Sonnax #104642-90SK — 6L90 Low/Reverse Sprag Repair Kit, when required.

Use the correct 6L90 sprag arrangement.

✔ Pump & Valve Body — Modified & Updated the Twisted Torque™ Way

The valve body is completely disassembled, cleaned, inspected, and rebuilt to correct known factory pressure-control problems.

Worn valves, pressure loss, sticking clutch-select valves, and converter clutch regulator problems are addressed during the rebuild.

Our Street calibration is set up for dependable clutch holding pressure and controlled shifts without unnecessarily harsh engagement.

✔ TransGo TCC & Clutch-Select Valve Corrections

Builder Reference: TransGo 6L8 CS-TCC and applicable SK 6L80 repairs.

These updates address known converter clutch regulator and sticking clutch-select valve problems.

They help prevent converter cycling, inconsistent lockup, delayed engagement, and misleading solenoid-performance complaints.

✔ Pressure Regulator & Boost Valve Updates

Pressure-regulator and boost-valve operation are inspected and corrected to address pressure loss and excessive pressure spikes.

Builder Reference: Applicable TransGo pressure-regulator repairs or Sonnax 6L90-compatible pressure-control updates.

Correct pressure control is important for clutch holding power, converter operation, and lubrication.

✔ Output Planetary Inspection & Lubrication

The output planetary assembly is inspected for worn pinions, bearing damage, heat marks, damaged gear teeth, and restricted lubrication.

Builder Reference: Sonnax #104584-90K — 6L90 Output Planet Saver Kit, where required.

Damaged or worn planetary parts are replaced.

✔ Complete Bushing Replacement

New replaceable bushings are installed throughout the transmission.

Shaft support, bushing fit, and running clearances are checked during assembly.

✔ New Gaskets, Seals & Sealing Rings

New internal gaskets, seals, and sealing rings are installed throughout the transmission.

Stator support and clutch-feed sealing surfaces are inspected for wear.

✔ New Transmission Filter

New transmission filter installed with every build.

✔ Internal Hard Parts Inspected & Measured

Input and output shafts, clutch drums, intermediate shaft, planetary assemblies, carriers, sun gears, hubs, bearings, and related parts are inspected for cracks, damaged splines, and wear.

Parts that fail inspection are replaced.

✔ Final Assembly, Clutch Clearance & Air Checks

Clutch packs are measured and set to the proper clearances.

Clutch assemblies are air-checked for proper apply operation before final assembly.

Shaft endplay and internal clearances are verified.

✔ Application-Specific Assembly & Setup

Every transmission is built for the correct engine, drivetrain, vehicle weight, and factory 6L90 configuration.

Truck, van, Camaro ZL1, CTS-V, 2WD, and 4WD applications are verified before assembly.

💥 SUPER DUTY BILLET COVER TORQUE CONVERTER — INCLUDED

Super Duty Billet Cover Torque Converter at stock stall speed, matched to the vehicle application.

✔ Super Duty Billet Cover

✔ Stock / Factory-Matched Stall Speed

✔ Matched to Engine & Vehicle Application

✔ Included With Every Twisted Street™ Build

No additional converter purchase required. It's already included.

A 6.6L work truck and supercharged Camaro ZL1 do not necessarily use the same converter. Each is matched to the correct application.

🔥 BUILT FOR

• Stock Camaro ZL1 and CTS-V automatic applications
• Silverado and Sierra 2500HD/3500HD gas trucks
• Heavy-duty Chevrolet Express and GMC Savana vans
• Stock and mildly modified 6.0L, 6.2L, and 6.6L GM engines
• Daily driving and commercial applications
• Towing and hauling within vehicle-rated limits
• Customers wanting factory-style drivability with known transmission weaknesses corrected

Target Rating: Up to 600 Engine HP

Engine torque, vehicle weight, towing loads, modifications, tuning, tire size, and intended use must be considered when choosing the proper build.

A 600 HP performance car and a heavily loaded commercial truck do not place the same demands on a transmission.

🚗 GM 6L90E VEHICLE APPLICATIONS

The Twisted Street™ 6L90E is built for select Chevrolet, GMC, and Cadillac vehicles originally equipped with the GM 6L90 / 6L90E six-speed automatic transmission (RPO MYD).

CHEVROLET

• 2007–2019 Silverado 2500HD / 3500HD — Select 6.0L gasoline V8 applications
• 2020–2023 Silverado 2500HD / 3500HD — Select 6.6L gasoline V8 applications
• 2012–2015 Camaro ZL1 — Supercharged 6.2L V8 automatic
• Express 2500 / 3500 — Select factory-equipped 6L90 applications; year, engine, and configuration verification required
• Suburban 2500 / 3500HD — Select heavy-duty factory 6L90 applications

GMC

• 2007–2019 Sierra 2500HD / 3500HD — Select 6.0L gasoline V8 applications
• 2020–2023 Sierra 2500HD / 3500HD — Select 6.6L gasoline V8 applications
• Savana 2500 / 3500 — Select factory-equipped 6L90 applications; year, engine, and configuration verification required
• Yukon XL 2500 — Select heavy-duty factory applications

CADILLAC

• 2009–2015 CTS-V — Supercharged 6.2L V8, factory six-speed automatic applications

ENGINE SWAPS & CUSTOM APPLICATIONS

We also build 6L90E transmissions for select heavy-duty LS swaps, performance vehicles, and custom applications.

Contact us with engine, transmission controller, drivetrain configuration, and intended use before ordering.

IMPORTANT FITMENT INFORMATION

This listing is for the GM 6L90 / 6L90E (RPO MYD) ONLY. It is NOT a direct replacement for the 6L80E (RPO MYC).

Not every vehicle within the listed year ranges was equipped with a 6L90.

Diesel/Allison transmissions, 6L80 applications, and later 10-speed-equipped vehicles are excluded.

VIN and factory transmission identification are required before ordering.

🔥 NEED MORE THAN STREET?

Twisted Street™ 6L90E is designed for factory-powered and mildly modified applications requiring dependable heavy-duty operation.

Planning higher horsepower, substantial engine modifications, aggressive tuning, oversized tires, or more demanding performance use?

Our Twisted Pro™, Twisted Punisher™, and Twisted Executioner™ 6L90E transmissions will offer additional clutch capacity, stronger internal shafts, and converter upgrades for approved high-load applications.

Tell us the vehicle. Tell us the motor. Tell us the modifications. Tell us how you're actually going to drive it.

We'll help match the right transmission to your build.

📞 833-858-9612

Twisted Torque™ — Built for the Application. Not the Catalog.