Continued movement of the steel valve within the aluminum bore. Lack of optimal valve and linkage stability creates wear and scoring of the manual valve bore, reducing line pressure in reverse and manual low positions.
The Sonnax oversized hard-coat anodized aluminum valve allows the valve bore to be refurbished, and has an increased stem diameter at the detent lever and an additional spool for increased stability.
Contact a Sonnax Parts Distributor.
There is visible wear in the manual valve bore or a proper vacuum test results in 9" or less.