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Sonnax Clutch Backing Plates

5.0 out of 5 stars 7 Customer Reviews

GM 6L80 and 6L90 transmissions often suffer failure of the 4-5-6 clutch assembly due to flexing and bowing of the backing plate (coning)—especially when your clutch-apply pressures exceed OE specifications. Sonnax clutch backing plates are designed to minimize flexing/bowing when the clutch is applied, drastically reducing the likelihood of clutch plate distortion. Their stiffer backing plate design outperforms OE and aftermarket plates.

Results 1 - 4 of 4

Clutch Backing Plate, 4L60, 700R4, 4L60E, 4L65E, 4L70E, Kit

Part Number: SOX-74140-01K

5.0 out of 5 stars ( 7 )

Estimated Ship Date: Today

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Estimated Ship Date: Today

Clutch Backing Plate, THM400, 4L80-E, Kit

Part Number: SOX-34144HD-01

Not Yet Reviewed

Estimated Ship Date: Today

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Estimated Ship Date: Today

Clutch Backing Plate, 4L80-E, 4L85-E, Kit

Part Number: SOX-34144HD-02

Not Yet Reviewed

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BACKING PLATE

Part Number: SOX-36965-03

Not Yet Reviewed

Estimated Ship Date: Oct 16, 2025 if ordered today

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Estimated Ship Date: Oct 16, 2025 if ordered today

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