Mid 2010-earlier GM 6L80E–6L90E applications have a tendency to set a P0751 (shift solenoid 1 malfunction) code. One of the causes of this is the OE spring force at the clutch select valves inhibiting movement of the valves, affecting proper control of clutch apply fluid. Early-model production has updates made to reduce the spring force, however the updated springs are not available separately from OE, only as part of a new and expensive lower valve body. Sonnax clutch select valve spring kit updates these springs to the correct lower load to prevent the P0751 code.