摘要 |
A replacement 1-2 shift valve for an automatic transmission, which restores a smooth shift from first to second gear thereby correcting a shudder shift or a complete failure to shift from first to second gear is disclosed. The present 1-2 shift valve comprises a valve piston including at least one bi-directionally tapered valve stem that changes the direction of transmission fluid flow within the valve such that a rebound force is generated which acts to propel the valve piston in an axial direction toward the second gear position of the valve. The piston lands which comprise the valve piston are provided with a plurality of annular grooves that function to retain transmission fluid and to center the valve piston in its mating bore to resist to side loading during operation. In addition, the present valve piston is provided with an anodized surface finish, which increases service longevity.
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