transmission troubles

[Miner5.9er]

05 5.9 cummins 2500 quad cab short box*
transmission shifts from 2nd to 3rd fast when I'm slowly picking up speed, and then holds 3rd longer than it should and feels like it barely has any pick up...once it shifts into 4th it accelerates fine....been looking around and googling a bunch but I want insight from someone who's had/having the same problem*

 

[DonFitzwater]

Sounds like a valve body problem.......but you really should post this in the 5.9 section, not first time owners section because this area doesn't get as much traffic.