Upshift Issues 00 blazer

I have 00 Blzaer 4WD that holds all of its shift way too long. It eventually shifts at 3000 to 3500 RPMs with normal acceleration. No Slip and the fluid is clean. It will also downshift with a slight acceleration. If it were a 700 R4 I would just adjust the passing gear cable but no such luck with a computer controlled tranny. There are no codes and the check engine light is not on. Any help would be greatly appreciated.
:banghead:

Welcome to AF.
Make sure the engine running is good shape.
You need to get it on a engine/transmission capable scanner and see what is going on.
Read out all engine and transmission data and codes and look for stored and past and present codes transmission and engine both
Remember a engine has to be running good for the transmission to shift good.
Post back any codes from a good engine/transmission scanner.

It's been scanned with a snap on scanner and there are no codes. I have had an opinion on the TPS. We checked the TPS range and it is doing what it is upposed to do. Engine runs great no misses or sputters.

My most recent opinion is a check ball in the valve body.

When you had them check for codes did they look into the solienoid times it takes to shift or any compensation?