• 4L80-E
• 4L85-E
• TH400
• In 4L80-E units, part can be used in either early or late-model drums.

Wear at the direct clutch drum bore in GM TH400, 4L80-E and 4L85-E transmissions allows 3rd and Reverse apply oil to exhaust. This oil leakage can result in direct...Read More

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• 4L80-E
• TH400
• Fits all TH400 & '95-earlier 4L80-E.

OE cast aluminum servo pistons can be brittle and are prone to breaking. Sonnax heavy duty low/reverse servo piston 34914-01 for GM TH400 and '95-earlier 4L80-E tr...Read More

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• 4L80-E (Dual Stator)
• 4L80-E (Early Single Stator)
• 4L80-E (Late Single Stator)
• 4L80-E, 4L85-E, Multi-Plate Performance Converter
• Street/Strip applications only.

A performance torque converter is highly specialized based on the performance characteristics of the specific vehicle. Sonnax has several levels of kits to ensure ...Read More

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• 4L80-E (Dual Stator)
• 4L80-E (Early Single Stator)
• 4L80-E (Late Single Stator)
• 4L80-E, 4L85-E, Multi-Plate Performance Converter
• Street/Strip applications only.

A performance torque converter is highly specialized based on the performance characteristics of the specific vehicle. And Sonnax has several levels of kits to ens...Read More

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• 4L80-E (Dual Stator)
• 4L80-E (Early Single Stator)
• 4L80-E (Late Single Stator)
• 4L80-E, 4L85-E, Multi-Plate Performance Converter
• Street/Strip applications only. For use with GM 258mm early-style stators only.

A performance torque converter is highly specialized based on the performance characteristics of the specific vehicle. Sonnax has several levels of kits to ensure ...Read More

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• 4L80-E (Dual Stator)
• 4L80-E (Early Single Stator)
• 4L80-E (Late Single Stator)
• 4L80-E, 4L85-E, Multi-Plate Performance Converter
• Street/Strip applications only. For use with GM 258mm early-style stators only.

A performance torque converter is highly specialized based on the performance characteristics of the specific vehicle. Sonnax has several levels of kits to ensure ...Read More

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• 4L80-E (Dual Stator)
• 4L80-E (Early Single Stator)
• 4L80-E (Late Single Stator)
• 4L80-E, 4L85-E, Single-Plate Performance Converter (Mounting Ring)

Sonnax performance converter mounting ring kit GM-RK-15 is designed to work with both early- and late-model GM 4L80-E, 4L85-E transmissions and utilizes the GM 245...Read More

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• 4L80-E
• 4L85-E
• '91-Later

Sonnax offers a genuine AC Delco pressure switch manifold for the 4L80-E unit.

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• 4L60-E
• 4L65-E
• 4L70-E
• 4L80-E
• 4L85-E

Tool kit for 77754-09K, 34200-16K, SC-4L80E and SC-4L60E.

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• 4L80-E
• 4L85-E
• TH400

Case bushing walkout and thrust washer wear are common issues in the GM TH400, 4L80-E and 4L85-E units.  Sonnax heavy duty case bushing kit 34006-SPB combines the ...Read More

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• 4L80-E
• 4L85-E

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• 4L80-E
• 4L85-E
• TH400

A pump that has been resurfaced or accumulated shaft spline wear creates excessive endplay of the forward and direct drums. This reduces sealing ring, clutch, bear...Read More

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• 4L80-E
• 4L85-E
• TH400

A pump that has been resurfaced or accumulated shaft spline wear creates excessive endplay of the forward and direct drums. This reduces sealing ring, clutch, bear...Read More

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• 4L80-E
• 4L85-E
• 4T60
• 4T60-E
• 4T65-E

34821-01 is a direct replacement for the planetary thrust bearing in listed units. This bearing is known to fail and destroy the planet gears. Replace the bearing ...Read More

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• 4L80-E
• 4L85-E
• Fits .668" dia. TCC valve bores.

OE end plugs are designed to prevent critical pressure loss by capping the bore, while also functioning as a valve stop. Repetitive spring motion, valve impact and...Read More

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• 4L80-E
• 4L85-E
• TH400
• TH425

Sonnax forward clutch hub front washer 34298-078 replaces the OE .063" thick washer in GM TH400, TH425, 4L80-E and 4L85-E transmissions between the forward clutch ...Read More

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• 4L80-E
• 4L85-E

Input shaft failure is a common problem in performance and heavy duty GM 4L80-E and 4L85-E transmissions. Sonnax heavy duty input shaft 34670-01 is manufactured fr...Read More

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• 4L80-E
• 4L85-E
• TH400

The OE case bushing in vehicles with a GM TH400, 4L80-E and 4L85-E transmissions tends to walk out of the housing bore. This leaves the output shaft unsupported, r...Read More

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• 4L80-E
• 4L85-E
• TH400
• TH425

Sonnax extreme duty forward clutch hub kit 34322-02K is manufactured from forged 4140 steel and features nitrited and case-hardened splines to eliminate spline wea...Read More

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• 4L80-E
• 4L85-E
• Output & reaction planetaries, '99-later

The output and reaction planetary pinion assemblies in '99-later 4L80-E transmissions frequently wear out and must be rebuilt or replaced. New replacement assembli...Read More

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• 4L80-E
• 4L85-E
• Output & reaction planetaries, 1999 & Later

The output and reaction planetary pinion assemblies in '99-later 4L80-E transmissions frequently wear out and must be rebuilt or replaced. New replacement assembli...Read More

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• 4L60-E
• 4L65-E
• 4L70-E
• 4L80-E
• 4L85-E
• For use with early-style ('92–'02) EPC solenoid in late-style (’03-later) units, solenoid not included.

GM 4L60-E, 4L65-E, 4L70-E, 4L80E-, 4L85-E  transmissions have both early- and late-style EPC solenoids. The early-style (’92-’02) proved to be more reliable than t...Read More

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• 4L80-E
• 4L85-E
• TCC & PR Valves

OE end plugs are designed to prevent critical pressure loss by capping the bore, while also functioning as a valve stop. Repetitive spring motion, valve impact and...Read More

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• 4L80-E
• 4L85-E
• TH400
• TH425
• .005" Thick

Sonnax offers two solutions for excessive endplay in GM TH400, TH425, 4L80-E and 4L85-E units. Sonnax rear unit endplay shim 34006-05 can be stacked under the four...Read More

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