727 Trans question.

It was a poor rebuild sorry, most cases it is front pump drain back that is the no pressure no reverse delay. Worn pump and bushings.

Most likely unfortunately the rebuilder did not check all the clearances, replace all thrust washers, and bushings etc.Setup correct clearances on input shaft to out put shaft, drum clearance specs etc. for clutch packs the works. Sounds like a quickie rebuild to me.

Most rebuilds are at best soft parts and seals only. I would pull it out and have it done the 100% correct way! Sorry:)