• 68RFE
• 68RFE, Multi-Plate Performance Converter
• A618, 47RH/RE, 48RE (310mm), Multi-Plate Performance Converter
• BorgWarner 310mm LU (A618, 47RH/RE, 48RE)
• Buick TH350
• TH400 (3L80), AT-540
• Conversion for BW 310mm LU (A618), GM TH400 (3L80), AT-540 & Buick TH350.

Sonnax conversion spacer GMBW-WS-40 and outer stator race GM-R-15 are used with the GM 300mm outer stator race, springs and rollers for a cost-effective upgrade to...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
• 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
• 4L85-E
• Fits units '95-later.

Vehicles with '95-later GM 4L80-E and 4L85-E transmissions commonly exhibit wear in the Reverse checkball sleeve located in the 3-4 shift valve bore. This issue is...Read More

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• 4L80-E
• 4L85-E

GM 4L80-E and 4L85-E units may display no converter lockup or codes 68, 39, 1870 or P0741. Imbalance of torque converter clutch apply oil through the front stator ...Read More

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• 4L80-E
• 4L85-E
• Long version, fits ’95-later with external NSS.

Manual shift shafts in GM 4L80-E and 4L85-E models can become corroded in harsh environments. Corroded manual shift shafts are not suitable for reuse, especially i...Read More

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• 4L80-E
• 4L85-E

GM 4L80-E and 4L85-E transmissions may have 2nd gear starts and no upshifts, which can be accompanied by trouble codes 68, 85, 86 and/or 87. These problems can oft...Read More

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• 4L80-E
• 4L85-E
• Fits units '95-later.

Vehicles with '95-later GM 4L80-E and 4L85-E transmissions commonly exhibit wear in the Reverse checkball sleeve located in the 3-4 shift valve bore. This issue is...Read More

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• 4L80-E
• TH400
• For output and reaction planetaries, fits all TH400 and '98-earlier 4L80-E with .750" wide pinion gears.

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• 4L80-E
• 4L85-E

In 4th Gear, signal A oil force must overpower the 1-2 shift valve spring and opposing signal B pressure in GM 4L80-E and 4L85-E transmissions. If the 1-2 shift va...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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• 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

The actuator feed limit (AFL) valve in GM 4L80-E and 4L85-E units has a large reaction area and is greatly affected by side loading, which wears the valve body bor...Read More

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• 4L80-E
• 4L85-E
• Fits '91-later units with factory-style sleeve, no O-rings. Can be retrofitted to '89–91 units. See instructions for details.

Common problems in vehicles with GM 4L80-E and 4L85-E transmissions are uncontrollable line rise (upward of 500-600 psi), high line pressure in Reverse, buzzing no...Read More

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• 4L80-E
• 4L85-E
• TH400
• Updated 3-tang style shim fits all units, including '97-later 4L80-E and 4L85-E units.

It is often difficult to reduce front unit endplay on GM TH400 or 4L80-E and 4L85-E units with excessive spline wear. Normal component wear allows excess forward a...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

Sonnax Sure Cure kit SC-4L80E, fully compatible with '91-later GM 4L80-E and 4L85-E units, is a comprehensive reconditioning package featuring the best Sonnax prod...Read More

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• 4L80-E
• 4L85-E

GM vehicles equipped with 4L80-E and 4L85-E transmissions may exhibit problems such as TCC shudder, burnt converter linings, TCC apply and release concerns and rel...Read More

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• 4L80-E
• 4L85-E
• O-Ring style. Kit can be retrofit to back to '89 units. See instructions for details.

Common problems in vehicles with GM 4L80-E and 4L85-E transmissions are uncontrollable line rise (upward of 500-600 psi), high line pressure in Reverse, buzzing no...Read More

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• 4L80-E
• 4L85-E
• Fits TCC shift valve bore with .497" dia.

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

GM vehicles equipped with 4L80-E and 4L85-E transmissions may exhibit problems such as TCC shudder, burnt converter linings, TCC apply and release concerns and rel...Read More

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• 4L80-E
• 4L85-E
• With encapsulated relief valve. O-Ring style

Common problems in vehicles with GM 4L80-E and 4L85-E transmissions include uncontrollable line rise (upward of 500 psi), high line pressure in Reverse, broken dir...Read More

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• Powerglide
• Powerglide, TH350, TH400 (258mm) Performance Converter
• TH400 (3L80), AT-540

Sonnax 258mm performance converter kit GM-RK-358 for 35-spline GM Powerglide and TH400 258mm applications allows builders to assemble a high performance converter ...Read More

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• 4L80-E
• 4T65-E
• TH400
• For output and reaction planetaries, fits all TH400, 4T65-E and '98-earlier 4L80-E with .750" wide pinion gears.

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