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8L90 Valve Body Parts Unavailable

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My 2019 Sierra with 12,00 miles under warranty was diagnosed by the dealership.

Was told the valve body need replacement that was 7 days ago now I’m being told a replace valve body is not available and they don’t have an eta for the part.  


Primary issue is the torque converter clutch disengages every 5-10 seconds at highway speed, in town it is much worse. Secondary problem torque converter clutch disengages the vehicle shimmies also at low speeds has a harsh shift.  

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The problem is the Torque Converter Clutch (TCC) line pressure is bleeding off causing the TTC to unlock.  The computer senses the slip condition and resends the command the reengage the TCC, the cycle repeats in an endless loop.  The TCC will eventually wear out and fail to lock.

Replacing the valve body is the first step because it is the easiest.

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