'89-'95 722.3s installed in some models have a shift delay feature that is active during cold start /driveaway conditions. If that delay does nor cancel after a certain temp is reached, the additional transmission control pressure will be maintained even with coastdown throttle. The culprit can be either electrical or vacuum related.
Are the 3-4 & 4-3 shifts OK?

Yes, 3-4 shifts and 4-3 shifts are okay. Where is the shift delay located?

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1989 300CE