727 slips into 3rd

[44070dart]

I have a 727 forward manual valve body trans hooked to a 440. 1st and 2nd are fine shifting up. It's 3rd that is the problem. When shifting into 3rd the trans slips, and then catches.The delay is a second or two, but then it's fine. No slipping once in third, just at the shift point. Thanks for any suggestions

 

[Bewy]

Sounds like a valve body problem. Sticking valve in the VB or leakage between the VB & case. separator plate.