I just replaced my 700-R4 with 350 and whenever I drive it for a while and it warms up it doesn't shift right. What happens is I'll have it in drive and it'll just downshift by itself into 2nd and won't go back into drive. If I shift it manually into 2nd and then to drive it will go in to drive but it'll downshift within a few seconds. It's not the kickdown cable. I'm really stumped on this one. Can anyone help? TIA.

 

Directs slipping?

 

I thought if it slipped it would slip all the time, not just when it warmed up. But I don't know. I know all the clutches are good though. The transmission was apart and they were brand new.