Truck Doesn't Like To Downshift

[lt1transam]

2003 2wd 5.3 with tow pkg. Truck has great/smooth midrange power and acceleration. It just will hardly downshift under a hard acceleration like when getting on the interstate. It just chugs along feeling very under-driven. Anybody else have this issue?

[jblakeney]

Right from my ATSG 4L60e manual.

 

No Part Throttle or Delayed Down shifts.

 

1 -> 2-4 servo assembly ----- Servo cover retaining ring omitted or misassembled ----4th apply piston damaged or misassembled ---- servo inner housing damaged or misassembled

 

2 -> valve body assembly ----- 3-2 downshift valve stuck ----- sequence valve body channel blocked.

 

Any DTC's???????? I am assuming nobody has been working on the transmission and nobody has done a servo upgrade....

 

Jbo