Anyone had these symptoms with a 904?

A 2-3 flare accompanied by a delayed reverse engagement means worn direct clutch. It's the first drum behind the pump. This is an easy fix. Pull out the pump and drop out the two front drums and front band. Put the pump in a vise and put the direct drum on it with new clutches with around .040 to .080 clearance and air check it to test the seals and rings. If they're good; leave them; at least leave the seals, changing rings isn't too hard. Same deal with the forward clutch. And if the front band is black or worn down replace that too. Put it back together with a new front seal, large o-ring and gasket. I wouldn't recommend changing the seals if they pass the pressure test because they do take some finesse and are easy to mess up.