8L90 Vacuum Testing - Transmission Digest

8L90 Vacuum Testing

Below are the diagrams for vacuum testing GM 8L90 transmissions. Note: OE valves are shown in rest position and should be tested in rest position unless otherwise indicated. Test locations are pointed to with an arrow. Springs are not shown for visual clarity. A low vacuum reading indicates wear. For specific vacuum test information, refer to additional information available at www.sonnax.com.

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