[fordteacherguy]

A possible cause of weird flares is end play out of specs affecting sealing ring performance especially considering hard parts replaced that might change stacked clearances. End play spec is .004-.044 but I prefer under .020 or less for race trans and near the low end if it is rollerized. There is not much going on inside one of these...Excessive direct clutch clearance or band adjustment way off will affect the 2-3, but not 1-2.

Those are the most common problems I see if the VB was the same and worked fine before. Probably something simple....I share with my students my 4 rules of auto trans.

always check the pump
always check end play
always check clutch clearances
always air check before VB goes on.
If it passes these 4 checks the worst you usually have is a VB problem which you can fix in the car..all the rest, its coming back out!