The 2-3 shift has a flare or flare/bump before or after overhaul.
One possible cause is excessive sealing ring to ring groove side clearance at the overdrive clutch sealing rings. The sealing rings can wear into the ring groove, and when the clearance between the side of the sealing ring and the ring groove exceeds .005" the sealing rings will leak.
Measure the clearance between the side of the sealing rings for the overdrive clutch and the ring groove with feeler gauges. The overdrive clutch sealing rings are the two smaller rings on the inside of the rear cover. If there is excessive clearance, the rear cover must be replaced.
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