telling tranny mods by driving

Shift overlap. I had that in one of the valve bodies I have. I installed it brand new, and withthe car in the air I was just shifting thru the gears. When I pulled it into second, it locked up. Third gear was fine.
Sent it back and they fixed it, but it was very slow shifting from 2nd to 3rd. I thought it was my rebuild.
I put a different valeve body in and the tranny shifted hard into all gears. That is untill reverse left one day.