Trans acting very strange

[Blkt6]

Just had the tranny rebuild a few months ago and its acting up.Just cruising through the gears at differnt time something holds the car back.Feels like your dragging a trailor or something and then releases and the car drives normal.Then 10 minutes later does it again.Also a few times when letting off the gas around 40-45 the car slows down heavy like down shifting in a stick shift.Any Ideas HELP!!!!!

 

[MeanBuicks]

Is this happening primarily with the shifter in the overdrive position?

Have you had it back to the transmission builder since it started acting up?

 

[Blkt6]

Tranny

Yes, I always drive with the car in the overdrive position.Do you have any ideas,its going back to the shop on monday.Thanks for any help!