Extension Housing Bushing (Longer) for GM TH375 TH400 Turbo 400 Transmission

Extension Housing Bushing (Longer) – Compatible with GM TH375 & TH400 Turbo 400 / 3L80 Transmissions OEM Part Reference: #8619943

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What This Part Is:

This is the longer-style extension housing bushing for GM TH375 and TH400 (Turbo 400 / 3L80) transmissions. It is a precision aftermarket replacement manufactured to OEM specifications, cross-referencing GM part number 8619943. This bushing is pressed into the rear of the transmission's extension (tail) housing and supports the slip yoke, which connects the transmission output shaft to the driveshaft.

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Why You May Need This Part:

The extension housing bushing is a wear item that deteriorates over time, especially under the demands of high-mileage or high-performance use. Signs that this bushing needs replacement include:

• Noticeable vibration while driving, especially at highway speeds
• Clunking or banging when transitioning between acceleration and deceleration
• Transmission fluid leaking from the rear seal area
• Visible lateral movement or slop in the driveshaft yoke when the driveshaft is removed
• Scoring or uneven wear on one side of the slip yoke

Replacing this bushing restores proper yoke support, protects the rear output shaft seal, and eliminates drivetrain looseness.

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The Longer Variant — Important Sizing Note:

The TH400 and TH375 use more than one extension housing bushing size. This listing is for the longer version, designed for specific housing configurations. Before purchasing, please measure your existing bushing's outer diameter and length and compare to this part. If you are unsure which bushing you need, reach out — we're happy to help you confirm fitment.

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Fitment Information:

Compatible with GM TH375 and TH400 (Turbo 400 / 3L80) transmissions, 1964 and up, installed in:

• Buick – Full-size models, Riviera, LeSabre, Electra, and others with TH400
• Cadillac – DeVille, Fleetwood, Eldorado, and others with TH400
• Chevrolet – Camaro, Corvette, Chevelle, Impala, C/K Trucks, and others with TH400 or TH375
• Oldsmobile – Cutlass, 442, Delta 88, Toronado-based applications, and others
• Pontiac – Firebird, GTO, Bonneville, and others with TH400 or TH375

The TH375 was used from 1972–1976 in smaller displacement GM vehicles. It shares this bushing with the TH400 family.

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OEM / Cross Reference Numbers: 8619943